# GH+KH RO Reminiralzation Product Help.



## CJayT (18 Apr 2020)

Soooo, i've been really wracking my brain here about the best product to use to remineralize my ro water. Ideally I  wanted to raise both kg and gh. I have a 250ish L aquarium so want a relatively cheap solution. My water is high in nitrates (35-40ishppm) so cutting it with ro isn't really an option and salty shrimp is out of the question due to price. I came across  Aqua Source GH and KH buffer and wondered if it would be a good choice even though it is aimed at ponds... Can't seem to find a list of ingredients though?


----------



## Zeus. (18 Apr 2020)

CJayT said:


> Aqua Source GH and KH buffer and wondered if it would be a good choice even though it is aimed at ponds... Can't seem to find a list of ingredients though?



Salts are salts , but yes the percentages per mass if elements/compounds would be very helpful 



CJayT said:


> My water is high in nitrates (35-40ishppm) so cutting it with ro isn't really an option



Why not - free NO3

Might be worth having a look at *Fert Cal V1.6 beta *works out the dkH and  dkH form your water report and RO mix and has some salts you can use to get to your targets, if a salt/product isn't on which you would like to use give us a nudge and I will add it


----------



## zozo (18 Apr 2020)

Epsom is used as fertilizer as a Magnesium source, this will raise GH. 

Baking Soda is a Bicarbonate that is used to raise KH.
Pond products sold as KH Plus is actually the very same thing it's Natrium Bicarbonate, but the package doesn't always specify the contents. It also can be bought as a cleaning Agent/Soda, the very same stuff for 3 different applications. In 3 different price ranges, just make sure it is Natrium Bicarbonate and you're good to go for raising KH

Pond and aquarium products soled as GH Plus contain Calcium and Magnesium. If you want to add Calcium only next to the Epsom you can use Calcium carbonate also available as a powder in most pharmacies.


----------



## dw1305 (18 Apr 2020)

Hi all, 





CJayT said:


> best product to use to remineralize my ro water.


Welcome, and look no further, you are in the right place. <"A DIY mix is the way forward">.  

As the other have said once an ion is in solution it doesn't matter where it came from, and dry salts are just so much cheaper in the long run. 





Zeus. said:


> Might be worth having a look at *Fert Cal V1.6 beta *works out the dkH and dkH form your water report and RO mix and has some salts you can use to get to your targets


Job done. Another option would be an aragonite calcium carbonate (CaCO3) source, like <"oyster shell chick grit"> or <"cuttle"fish" "bone">.  





CJayT said:


> My water is high in nitrates (35-40ishppm) so cutting it with ro isn't really an option


If you have a hard tap supply you can still cut your RO with tap water, you may only need 10% tap to give you some dGH/dKH. 

One of the great advantages of planted tanks is that plants are <"extremely efficient at assimilating all forms of fixed nitrogen">, which means that you don't get a build up of nitrate (NO3-).  I like a floating plant in all the tanks, partially because it has <"access to aerial CO2">, and partially because you can use it <"to assess water quality">.

cheers Darrel


----------



## CJayT (18 Apr 2020)

zozo said:


> Epsom is used as fertilizer as a Magnesium source, this will raise GH.



Thanks for all the replies guys. I should have mentioned I intend to EI dose and I also have a fair bit of Seriyu stone in my aquarium. Think I might end up going the DIY route. I've ordered a TDS meter too going to aimfor 120-140. I'm not sure why i'm so afraid of DIY... I've heard people say they're always chasing the ph with bicarb?

Another thing(sorry), when I do a water changes with new r/o water that is remineralised... How do I go about keeping the water chemistry consistent and not end up over concentrating everything?


----------



## Zeus. (18 Apr 2020)

dw1305 said:


> Another option would be an aragonite calcium carbonate (CaCO3) source, like <"oyster shell chick grit"> or <"cuttle"fish" "bone">.



With the aid of my Fert calculator, I worked out how much uptake of CaCO3 there would be with its salt solubility saturation of 0.015 grams per litre at room temp.

which for my 484 litre tank would be a weekly dose of 7.26grams of CaCO3




So 'if' my maths is correct adding some CaCO3 in excess to any tank should yield the same results of  ≈ 0.85°dKH and ≈ 0.81°dGH and if the CaCO3 is in excess it should maintain those minimum values


----------



## dw1305 (18 Apr 2020)

Hi all,


CJayT said:


> How do I go about keeping the water chemistry consistent and not end up over concentrating everything?


I use a conductivity (TDS) meter to give me a <"datum range where plant growth is acceptable">. Because you will be changing a large volume of water with EI you will probably find that you don't get a large salts build-up.


CJayT said:


> I've heard people say they're always chasing the ph with bicarb?


It is to do with pH as a measurement, the issue there is that <"pH is a really strange measurement">, and a lot of the conversation is based on the theory that all pH variation is dangerous and must be avoided at all cost. There is a certain amount of truth in this, but what it really means is that large changes in water chemistry aren't good for fish. The "pH stability" idea is to some degree fuelled by some (fairly misleading) advertising <"from the sellers of pH buffers etc">.

Where I would start is that in hard water large changes in water chemistry are required to change pH, but as the water gets softer this relationship breaks down, and by the time you get to pure H2O, pH is a meaningless parameter. Have a look at Diana Walstad's "Star Lake" section  in <"TDS and remineralizing.....>.

I didn't know anything about CO2 injection until I joined this forum, but as soon as I found that the people who injected CO2 had a pH drop of one unit when the CO2 is on, followed by a rapid rise of one unit when they turn it off, and their fish were fine. From that I knew that it wasn't pH variation in itself that was the problem. When you add CO2 you haven't changed the alkalinity, you've just changed the <"amount of TIC"> and moved the CO2 ~ HCO3- ~ pH equilibrium towards CO2, and this <"extra dissolved H2CO3 has depressed the pH">.

Even in heavily carbonate buffered situations you can drastically alter the pH just by photosynthesis, in both <"eutrophic"> and <"fairly clean water">.

cheers Darrel


----------



## Wookii (31 May 2020)

dw1305 said:


> Hi all, Welcome, and look no further, you are in the right place. <"A DIY mix is the way forward">.
> 
> As the other have said once an ion is in solution it doesn't matter where it came from, and dry salts are just so much cheaper in the long run. Job done.



Hey Darrel,

I’m thinking of moving to RO myself, and fancy trying the James Planted Tank DIY remineralising mix I’ve seen you suggest on a number of threads. I have a couple of questions though:

Firstly, I can write everything I know about chemistry on the back of postage stamp, so can I just check that these are the correct compounds:

Calcium Chloride Dihydrate: https://www.amazon.co.uk/dp/B07TRYH75R/ref=cm_sw_r_cp_api_i_vB.0EbJCEH8AX

Calcium Sulphate Dihydrate: https://www.amazon.co.uk/dp/B07CW1PCKN/ref=cm_sw_r_cp_api_i_nz.0EbEP2DRW0

Magnesium Sulphate Heptahydrate: https://www.amazon.co.uk/dp/B007DGMAIE/ref=cm_sw_r_cp_api_i_JC.0EbMS0JX9J

Potassium Carbonate: I can seem to find this, and have read it can be a little more tricky to keep and handle, so I’m planning to substitute for Potassium Bicarbonate:
https://www.amazon.co.uk/dp/B076634M48/ref=cm_sw_r_cp_api_i_eF.0EbVH9MTEV

Secondly, I plan to automate the generation of the water for the aquarium, so I need to be able to auto-dose premixed liquid salts into the RO tank.

Am I okay to mix the correct ratio of salts with some RO water, as I would for EI fert salts - i.e. there won’t be any strange interactions or other issues with the salts being kept in solution? Would I need to add some Potassium Sorbate if it’s being dosed over a couple of months?


----------



## Zeus. (31 May 2020)

Wookii said:


> Magnesium Sulphate Heptahydrate: https://www.amazon.co.uk/dp/B007DGMAIE/ref=cm_sw_r_cp_api_i_JC.0EbMS0JX9J



Mucher cheaper on Ebay



Wookii said:


> Secondly, I plan to automate the generation of the water for the aquarium, so I need to be able to auto-dose premixed liquid salts into the RO tank.
> 
> Am I okay to mix the correct ratio of salts with some RO water, as I would for EI fert salts - i.e. there won’t be any strange interactions or other issues with the salts being kept in solution? Would I need to add some Potassium Sorbate if it’s being dosed over a couple of months?



If I was to go down the RO route I would use 'dry salts' to add the minerals back to the RO water when doing WC.


----------



## Wookii (31 May 2020)

Zeus. said:


> Mucher cheaper on Ebay



Thanks Zeus - I did see the eBay offerings on the Google search - I’m just a little cautious that I’m actually getting what’s being advertised. Have you used that one yourself?




Zeus. said:


> If I was to go down the RO route I would use 'dry salts' to add the minerals back to the RO water when doing WC.



My water changes are daily and fully automated, so dry salts aren’t really an option.


----------



## Nick72 (31 May 2020)

I successfully use MgSO4.7H20 (Epsom Salts) for Magnesium, also to raise dGH.

CaSO4.2H20 (Calcium Sulfate Dihydrate / Gypsum) for Calcium, also to raise dGH.

I was using CaCO3 (Calcium Carbonate) for Calcium and additional dKH + dGH, but it does not dissolve well and I found my plants were covered in a dusting of CacO3 that was blocking photosynthesis and creating a anchor point for other organics + algae, so I've gone back to bags of crushed coral for the dKH as released slowly it doesn't have the same dusting issue.


----------



## Zeus. (1 Jun 2020)

Wookii said:


> My water changes are daily and fully automated, so dry salts aren’t really an option.



So makes it a little tricky. I was only looking at Seachems Equilibrium the other day/week. they used all sulphates

But then the solubility for CaSO4 isnt great but doable IMO.

so for 100l tank a clone of Seachems Equilibrium










the result above for CaSO4 show it for the dry dose weekly which accounts for the SSL with CaSO4 







So the SSL for CaSO4 is close to its limit !!! maybe a fine tune needed 

(Little sneak preview of the 'MTS wizard' in action above in V1.9 - Multiple tanks 🥰)




Nick72 said:


> I was using CaCO3 (Calcium Carbonate) for Calcium and additional dKH + dGH, but it does not dissolve well and I found my plants were covered in a dusting of CacO3 that was blocking photosynthesis and creating a anchor point for other organics + algae, so I've gone back to bags of crushed coral for the dKH as released slowly it doesn't have the same dusting issue.



CaCO3 does have a very low SSL ( see last pic above) so once it is saturated in the tank the dust/powder remains, however using larger particles they easily fall to the substrate level so out of sight for same result without the dusting of plants


----------



## Wookii (1 Jun 2020)

Zeus. said:


> So makes it a little tricky. I was only looking at Seachems Equilibrium the other day/week. they used all sulphates
> 
> But then the solubility for CaSO4 isnt great but doable IMO.
> 
> ...



Thanks Zeus, that’s awesome. So the Calcium Sulphate is going to be the sticking point.

The James Planted Tank recipe is (ignoring the Kh for now):

0.4g Calcium Chloride Dihydrate
2.0g Calcium Sulphate Dihydrate
2.0g Magnesium Sulphate Heptahydrate 
25 litres Water

I’m planning on changing 75 lites per day on the new tank, so I assume I’ll need 3x that, i.e.:

1.2g Calcium Chloride Dihydrate
6.0g Calcium Sulphate Dihydrate
6.0g Magnesium Sulphate Heptahydrate
75 litres Water

So from your spreadsheet, I’d need 3 litres of water to dissolve those 6.0g of Calcium Sulphate - am I reading that correctly? That’s a bit of a blow to morale - I was hoping to get it all done in a couple of hundred ml lol

It’s still doable, but means I probably need to up the size of the salt mixture storage tank to  60 litres+ to get a few weeks worth in there.

Is there another alternative to the Calcium Sulphate? I assume Sodium Chloride can’t just be straight substituted as it’ll add too much Chloride?

PS - that spreadsheet is awesome - you really need to get it integrated on a webpage, you could add some Google advertising then and make a few quid off your efforts!


----------



## dw1305 (1 Jun 2020)

Hi all, 





Wookii said:


> So from your spreadsheet, I’d need 3 litres of water to dissolve those 6.0g of Calcium Sulphate - am I reading that correctly?


You are,  but there is a way to increase the solubility of  CaSO4.2H2O, which is to cool the solution. Most salts are endothermic and more soluble at higher temperatures, but calcium sulphate is exothermic (heats up when it goes into solution) and cooling it increases the solubility. You would need to store the solution in the fridge to keep the calcium in solution.





Wookii said:


> Is there another alternative to the Calcium Sulphate?


Yes more calcium chloride (CaCl2.6H2O), it is very soluble, in fact it is so soluble it is really difficult to stop it liquefying.

You aren't particularly interested in the anion, because you are only adding small amounts, calcium nitrate (Ca(NO3)2.4H2O) would be another option. 

cheers Darrel


----------



## Wookii (1 Jun 2020)

dw1305 said:


> Hi all, You are,  but there is a way to increase the solubility of  CaSO4.2H2O, which is to cool the solution. Most salts are endothermic and more soluble at higher temperatures, but calcium sulphate is exothermic (heats up when it goes into solution) and cooling it increases the solubility. You would need to store the solution in the fridge to keep the calcium in solution.Yes more calcium chloride (CaCl2.6H2O), it is very soluble, in fact it is so soluble it is really difficult to stop it liquefying.
> 
> You aren't particularly interested in the anion, because you are only adding small amounts, calcium nitrate (Ca(NO3)2.4H2O) would be another option.
> 
> cheers Darrel



Thanks Darrel - refrigeration wouldn’t be practical unfortunately - I barely get enough room to keep my brine shrimp cysts in our fridge! Lol

When you say we aren’t interested in the anion - do you mean that in the case of Calcium Chloride, the chloride element is too small to be of any concern?

So could I swap all of the Calcium Sulphate for a mixture of Calcium Chloride and Calcium Nitrate?


----------



## dw1305 (1 Jun 2020)

Hi all, 





Wookii said:


> When you say we aren’t interested in the anion - do you mean that in the case of Calcium Chloride, the chloride element is too small to be of any concern?


I do.





Wookii said:


> So could I swap all of the Calcium Sulphate for a mixture of Calcium Chloride and Calcium Nitrate?


You could. All chloride and nitrate salts are soluble, but you may still have problems with the Ca++ ions interacting with the SO4-- (& HCO3-) ions in solution, and <"precipitating out">.

Personally I'm not too bothered in quantifying exactly how much dGH/dKH buffering I have, so I just cut the rain-water in the tanks with a small amount of tap water (about 18 dGH/dKH) to keep it within my <"conductivity datum range">.

I rarely actually measure the conductivity any more,  I use the <"state of the snail shells"> to give me a visual clue if the water has got very soft.

cheers Darrel


----------



## Zeus. (1 Jun 2020)

Wookii said:


> that spreadsheet is awesome - you really need to get it integrated on a webpage, you could add some Google advertising then and make a few quid off your efforts!



No it will be free for all to use, will be able to use it on only device, NO ADVERTS.




dw1305 said:


> calcium nitrate (Ca(NO3)2.4H2O)



Which was added on request for this reason of boosting the [Ca] when using RO water



dw1305 said:


> calcium chloride (CaCl2.6H2O),



Added on Calculator and you can pick any of the various six Hydrates to use - just have a little 'SSL' to add for each hydrate


----------



## Zeus. (1 Jun 2020)

Zeus. said:


> so for 100l tank a clone of Seachems Equilibrium



Opps I had selected 'TNC GH Boost' and not 'Seachems Equilibrium' for clone Wizard


----------



## Wookii (1 Jun 2020)

dw1305 said:


> Hi all, I do.You could. All chloride and nitrate salts are soluble, but you may still have problems with the Ca++ ions interacting with the SO4-- (& HCO3-) ions in solution, and <"precipitating out">.
> 
> Personally I'm not too bothered in quantifying exactly how much dGH/dKH buffering I have, so I just cut the rain-water in the tanks with a small amount of tap water (about 18 dGH/dKH) to keep it within my <"conductivity datum range">.
> 
> ...



Thanks Darrel - so how how much  Calcium Nitrate would I need to give the same dGH increase as 6.0g of Calcium Sulphate? And what ppm of Nitrate would that add?

Likewise for Calcium Chloride?

@Zeus.  would I be able to use the current version of your calculator to work all the above out?


----------



## dw1305 (1 Jun 2020)

Hi all, 





Wookii said:


> Thanks Darrel - so how how much Calcium Nitrate would I need to give the same dGH increase as 6.0g of Calcium Sulphate? And what ppm of Nitrate would that add?


You just need to work out the relative percentages of calcium (Ca) in each. You do this by adding together the RAMs for each element  (Ca = 40, O = 16 etc) to give you the RMM for the compound.

So for Ca(NO3)2.4H2O you have 40 + (14+(3*16))*2 = (40 + 124) = 164 for the Ca(NO3)2 and 4 * ((1+1) + 16) = 72 for the 4H2O giving you an RMM of 164+72 = 236. The percentage of calcium is 40/236 and ~17% Ca.

For CaSO4.2H2O the RMM is 172.2 and you have 40/172.2 = 23.3% Ca, as a ratio that is 1.37, so you multiply 6 * 1.37 = *8.22 g of Ca(NO3)2.4H2O*.

The NO3 is the same process, the percentage of NO3 in the calcium nitrate 124/236 =  52.5% and 52.5% of 8.22 = *4.32 g of NO3*.





Wookii said:


> Likewise for Calcium Chloride?


You would need to use the calculation for the <"hexahydrate"> (CaCl2.6H20)  the hexahydrate of calcium chloride  is the stable form, the dihydrate will absorb atmospheric moisture.

@Zeus. takes out all the hard work/fun from the question, by automating the same process.

cheers Darrel


----------



## Zeus. (1 Jun 2020)

Wookii said:


> Thanks Darrel - so how how much Calcium Nitrate would I need to give the same dGH increase as 6.0g of Calcium Sulphate? And what ppm of Nitrate would that add?
> 
> Likewise for Calcium Chloride?



Tank size and dose amount and Dose volume please



Wookii said:


> would I be able to use the current version of your calculator to work all the above out?



Thinks so but v1.8 is so different than V1.9 just the level off the checking. Its close to release- but happy to run your details thought it


----------



## Wookii (1 Jun 2020)

Zeus. said:


> Tank size and dose amount and Dose volume please
> 
> 
> 
> Thinks so but v1.8 is so different than V1.9 just the level off the checking. Its close to release- but happy to run your details thought it



The tank is 1500 x 450 x 450 so a sniff over 300 litres, though it will have a sump housing approx 35 litres also.

Water changes will be 75 litres daily. Standard EI dosing targets. 

If we assume a mixture of Calcium Nitrate and Calcium Chloride in an optimum proportion to replace the Calcium Sulphate?


----------



## dw1305 (1 Jun 2020)

Hi all, 





Wookii said:


> If we assume a mixture of Calcium Nitrate and Calcium Chloride in an optimum proportion to replace the Calcium Sulphate?


In terms of the Ca++ ions it doesn't make any difference which compound they came from, once they are in solution they are all the same.  The advantage of calcium nitrate would be that it would give you a useful anion.

I think calcium chloride is going to be  a lot easier to obtain than calcium nitrate.  

You can buy a kilo of food grade calcium chloride for ~£5. 

cheers Darrel


----------



## Zeus. (1 Jun 2020)

I've just realised that when we add 'TNC GH Boost' or 'Seachems Equilibrium' we dose it for the water added and NOT the Tank volume. Unless we are Filling the tank for the first time.

So I can use the calculator for a full tank and just the WC, but which one do you wish to clone  'TNC GH Boost' or 'Seachems Equilibrium' 

I also need to rethink/remove/adjust coding for  'TNC GH Boost' and 'Seachems Equilibrium' as at present it isn't 'fit for purpose' IMO


----------



## Wookii (1 Jun 2020)

dw1305 said:


> Hi all, In terms of the Ca++ ions it doesn't make any difference which compound they came from, once they are in solution they are all the same.  The advantage of calcium nitrate would be that it would give you a useful anion.
> 
> I think calcium chloride is going to be  a lot easier to obtain than calcium nitrate.
> 
> ...



That’s what I was thinking, that the nitrate would be useful, but didn’t want to add too much. If I’ve understood your calculations correctly, if I directly substituted the 6.0g of Calcium Sulphate I’d need 8.22g of Calcium Nitrate Which would add 4.32g of NO3, which in 75 litres is 4.32g/75litre x 1000 = 58mg/l which is too far above the EI target of 20-30ppm.

Given that I assume the Calcium Chloride is the better option, as you point out above. I’m just concerned about excessive build up of Chloride but you are suggesting that’s not a problem?


----------



## Wookii (1 Jun 2020)

Zeus. said:


> I've just realised that when we add 'TNC GH Boost' or 'Seachems Equilibrium' we dose it for the water added and NOT the Tank volume. Unless we are Filling the tank for the first time.
> 
> So I can use the calculator for a full tank and just the WC, but which one do you wish to clone  'TNC GH Boost' or 'Seachems Equilibrium'
> 
> I also need to rethink/remove/adjust coding for  'TNC GH Boost' and 'Seachems Equilibrium' as at present it isn't 'fit for purpose' IMO



I wasn’t particularly looking to clone either, just use the James Planted Tank DIY mix, but substituting the low solubility Calcium Sulphate with Calcium Chloride/Nitrate:

http://www.theplantedtank.co.uk/RO.htm

Yep, at this point I’m only looking at the daily 75 litre water change - I can just multiply everything by 4 for a full tank fill, and could just do that with dry salts as it’s a one off.

I also obviously want to use the lowest possible daily dosing volume so I can get the maximum number of doses from a 30-60 litre container of premixed salt solution. For that reason Sodium Chloride appears to be the prime candidate given its very high solubility.


----------



## dw1305 (1 Jun 2020)

Hi all, 





Wookii said:


> I also obviously want to use the lowest possible daily dosing volume so I can get the maximum number of doses from a 30-60 litre container of premixed salt solution. For that reason Sodium Chloride appears to be the prime candidate given its very high solubility.


Sodium chloride (NaCl) doesn't give you any dGH (multivalent cations) or dKH (HCO3-) ions, did you mean calcium chloride?

NaCl is in a lot of the re-mineralising mixes, with some blurb about "osmotic balance", but it is really just there as the cheapest possible filler. 

cheers Darrel


----------



## Wookii (1 Jun 2020)

dw1305 said:


> Hi all, Sodium chloride (NaCl) doesn't give you any dGH (multivalent cations) or dKH (HCO3-) ions, did you mean calcium chloride?
> 
> NaCl is in a lot of the re-mineralising mixes, with some blurb about "osmotic balance", but it is really just there as the cheapest possible filler.
> 
> cheers Darrel



Sodium was a typo Darrel, I meant Calcium Chloride - I told you my chemistry expertise fitted on a postage stamp!!


----------



## dw1305 (1 Jun 2020)

Hi all,





Wookii said:


> Sodium was a typo Darrel, I meant Calcium Chloride - I told you my chemistry expertise fitted on a postage stamp!!


I thought you probably did, but I just thought I'd check.

If you are going to dose EI, I would only add a smaller amount of calcium and you are dosing magnesium anyway (as part of the EI).  Plants don't have a huge calcium requirement, so if you are changing water regularly then you will constantly replenish it with your water change.

If I didn't have access to hard tap water supply I would go down the <"Oyster Shell Chick Grit"> route.





Zeus. said:


> With the aid of my Fert calculator, I worked out how much uptake of CaCO3 there would be with its salt solubility saturation of 0.015 grams per litre at room temp.
> 
> which for my 484 litre tank would be a weekly dose of 7.26grams of CaCO3
> 
> ...


cheers Darrel


----------



## Wookii (1 Jun 2020)

dw1305 said:


> Hi all,I thought you probably did, but I just thought I'd check.
> 
> If you are going to dose EI, I would only add a smaller amount of calcium and you are dosing magnesium anyway (as part of the EI).  Plants don't have a huge calcium requirement, so if you are changing water regularly then you will constantly replenish it with your water changes.
> 
> cheers Darrel



My main issue is maintaining sufficient calcium for the shrimp - to prevent any moulting issues, whilst also keeping the water soft enough for my Rasbora (for which I think my tap water is proving to hard at 13dGH - I’ve experienced quite a few losses). The ideal middle ground seems to be about 6dGh.

Within that I’d like to maintain the oft quoted 3:1 Ca:Mg ratio.

If it weren’t for the shrimp, then I’d do exactly as you suggest, and target 3dGH.

You are right though, I probably ought to Factor in the effect of the EI dosing on the GH.


----------



## Wookii (5 Jun 2020)

dw1305 said:


> Hi all, I do.You could. All chloride and nitrate salts are soluble, but you may still have problems with the Ca++ ions interacting with the SO4-- (& HCO3-) ions in solution, and <"precipitating out">.



Darrel, this point you make on precipitation - would this be permanent, or would regularly remixing with, say, an airstone, get the precipitation back into solution?


----------



## dw1305 (5 Jun 2020)

Hi all, 





Wookii said:


> this point you make on precipitation - would this be permanent


It would be difficult to re-solubilise a lot of the ions, it would depend upon the <"solubility rules">. In the case of carbonates, you could get the cation back into solution by acidifying  the solution, the "excess" inorganic carbon would be converted to CO2, and once that buffer had been lost the metals would go back into solution.

Heating and adding acid is your best bet, but for some compounds <"nothing will really help">, it is back to the <"iron oxide"> issue,  or @X3NiTH's post in <"DIY fertiliser...."> .

cheers Darrel


----------



## Wookii (5 Jun 2020)

dw1305 said:


> Hi all, It would be difficult to re-solubilise a lot of the ions, it would depend upon the <"solubility rules">. In the case of carbonates, you could get the cation back into solution by acidifying  the solution, the "excess" inorganic carbon would be converted to CO2, and once that buffer had been lost the metals would go back into solution.
> 
> Heating and adding acid is your best bet, but for some compounds <"nothing will really help">, it is back to the <"iron oxide"> issue,  or @X3NiTH's post in <"DIY fertiliser...."> .
> 
> cheers Darrel



Thanks Darrel - so in there a way of prevent the precipitation in the first place? Presumably by adding an acid? I didn't realise commercially available solutions were so acidic - but what type of acid and in what sort of quantities would I need to look for in a DIY mix?


----------



## dw1305 (5 Jun 2020)

Hi all, 





Wookii said:


> so in there a way of prevent the precipitation in the first place? Presumably by adding an acid?


Yes, by acidification. <"Commercially nurseries"> use <"nitric acid (HNO3) injection">, but I would <"keep away from strong acids"> and citric acid (C6H8O7) would be my weapon of choice. 

cheers Darrel


----------



## Wookii (5 Jun 2020)

dw1305 said:


> Hi all, Yes, by acidification. <"Commercially nurseries"> use <"nitric acid (HNO3) injection">, but I would <"keep away from strong acids"> and citric acid (C6H8O7) would be my weapon of choice.
> 
> cheers Darrel



Thanks Darrel, I have plenty of Citric Acid so that's a good option. (I also have ascorbic acid too?).  So should I be targeting a Ph of around 2-3? How much Citric acid per litre am I likely to require to achieve that?

Will this have any reaction with the Potassium Carbonate for the KH adjustment in the salt mix?

Also, I assume there are no negative effects of the Citric Acid when dosed into the aquarium?


----------



## dw1305 (5 Jun 2020)

Hi all, 





Wookii said:


> I have plenty of Citric Acid so that's a good option. (I also have ascorbic acid too?).


Yes, ascorbic acid (C6H8O6) is fine. These are both <"weak acids">, so they are much safer to handle. 





Wookii said:


> Will this have any reaction with the Potassium Carbonate for the KH adjustment in the salt mix?


Not with the potassium (K), but it will with the HCO3- ions, converting them to CO2, via the <"CO2 ~ HCO3- ~ pH equilibrium">. You would need to add the solution/salts to raise dGH/dKH separately. 





Wookii said:


> So should I be targeting a Ph of around 2-3? How much Citric acid per litre am I likely to require to achieve that?


Somewhere around there, I wouldn't worry about trying to work out an exact amount. Because it is going to be almost infinitely diluted in the tank water it doesn't matter if the pH dips lower in the all-in-one mix.

cheers Darrel


----------



## Wookii (5 Jun 2020)

dw1305 said:


> Hi all, Yes, ascorbic acid (C6H8O6) is fine. These are both <"weak acids">, so they are much safer to handle. Not with the potassium (K), but it will with the HCO3- ions, converting them to CO2, via the <"CO2 ~ HCO3- ~ pH equilibrium">. You would need to add the solution/salts to raise dGH/dKH separately. Somewhere around there, I wouldn't worry about trying to work out an exact amount. Because it is going to be almost infinitely diluted in the tank water it doesn't matter if the pH dips lower in the all-in-one mix.
> 
> cheers Darrel



Thanks Darrel. OK, a separate Kh solution of Potassium Bicarbonate and RO water should be okay as I should have a spare dosing pump given its a 4 pump unit. So I guess in practical terms I take some RO water, keep adding citric acid until I hit 2-3 Ph (just to work out a correct amount  for future mixes) then add the other salts and mix, maybe double checking the Ph has been maintained. Job done? 

The only things that is left that I'm unsure on is how much Calcium Chloride I should be adding to substitute the 6g of Calcium Sulphate in the James RO mix. I followed the link you gave me to the Salt Wiki, but I couldn't for the life of me glean the RAM values you mentioned in your previous post, for the  hexahydrate version, to attempt to calculate the Ca percentage?


----------



## Zeus. (5 Jun 2020)

dw1305 said:


> Because it is going to be almost infinitely diluted in the tank water it doesn't matter if the pH dips lower in the all-in-one mix.



Plus (correct me if I am wrong) a at lower pH the PO4 is less likely to react with the micro chelates in the AIO


----------



## X3NiTH (5 Jun 2020)

That’s a Screenshot from the webqc.org, very handy calculator, takes a bit of getting used to though when translating formulas to make it calculate more complex compounds.


----------



## X3NiTH (5 Jun 2020)

Zeus. said:


> Plus (correct me if I am wrong) a at lower pH the PO4 is less likely to react with the micro chelates in the AIO



Yes less likely but not impossible, any free unchelated Iron in the mix will be mopped up by the PO4, any conditions that degrade the chelate when it’s all in solution will result in increased precipitation.

I always found towards the end of use of a 500ml bottle of DIY AIO that there was always a milky brown precipitate, the things that could affect the mixture in the bottle are storage temperature, exposure to light and evaporation (as the liquid level in the bottle recedes due to dosing  the surface area to volume increases, which is why I’ve moved to IV bags).


----------



## Wookii (5 Jun 2020)

X3NiTH said:


> View attachment 149932
> 
> That’s a Screenshot from the webqc.org, very handy calculator, takes a bit of getting used to though when translating formulas to make it calculate more complex compounds.



Thanks @X3NiTH that's great - stupid question though I'm afraid - where is the Chloride?


----------



## Wookii (5 Jun 2020)

Zeus. said:


> Plus (correct me if I am wrong) a at lower pH the PO4 is less likely to react with the micro chelates in the AIO





X3NiTH said:


> Yes less likely but not impossible, any free unchelated Iron in the mix will be mopped up by the PO4, any conditions that degrade the chelate when it’s all in solution will result in increased precipitation.
> 
> I always found towards the end of use of a 500ml bottle of DIY AIO that there was always a milky brown precipitate, the things that could affect the mixture in the bottle are storage temperature, exposure to light and evaporation (as the liquid level in the bottle recedes due to dosing  the surface area to volume increases, which is why I’ve moved to IV bags).



Just to clarify guys, this is a RO remineralisation mix I'm trying to determine, so I won't be adding any trace elements - they'll be added via separate EI dosing - so there shouldn't be any issues with chelates I assume?


----------



## Wookii (5 Jun 2020)

OK, did I do this right:


----------



## Wookii (5 Jun 2020)

Assuming I got the formula above correct for the Calcium Chloride Hexahydrate that Darrel recommended, that's 17.28% Ca. So based on Darrel's calculations the Calcium Sulphate yields 23.3% Ca, that's a ratio of 1.348 - so to directly substitute 6.0g Calcium Sulphate in the James RO mix, I replace with 6.0 x 1.348 = 8.09g of Calcium Chloride ( CaCl2.6H20 ).

For the James mix, with the 1.2g of Calcium Chloride that is already included, that gives 9.29g in total of Calcium Chloride ( CaCl2.6H20 ) for the 75 litre water change.

That will mean adding 9.29g x 30.57% / 75 litres x 1000 = 37.9ppm of Chloride. Given my tap water has 61ppm Chloride per the Severen Trent water report, I assume that's not an issue at all?


----------



## X3NiTH (5 Jun 2020)

Ha ha yes I missed out the chloride!  Yup you got it right though!


----------



## dw1305 (5 Jun 2020)

Hi all, 





Wookii said:


> OK, did I do this right:


Right idea, wrong answer, you got a bit carried away with the hydrogen atoms (H), and a lot less carried away with the oxygen.

I think it should be: CaCl2.6H2O = 1 * Ca, 2 * Cl, 12 * H, 6* O so 40 + 71 + 12 + 96 = 219

RMM = 219 and 40/219 = 18.3% calcium





Wookii said:


> So based on Darrel's calculations the Calcium Sulphate yields 23.3% Ca, that's a ratio of 1.348 - so to directly substitute 6.0g Calcium Sulphate in the James RO mix, I replace with 6.0 x 1.348 = 8.09g of Calcium Chloride ( CaCl2.6H20 ).


23.3/18.3 = 1.22 and 6 x 1.22 = 7.33g of CaCl.6H2O.





Wookii said:


> That will mean adding 9.29g x 30.57% / 75 litres x 1000 = 37.9ppm of Chloride. Given my tap water has 61ppm Chloride per the Severn Trent water report, I assume that's not an issue at all?


No, I don't do think so.

cheers Darrel


----------



## X3NiTH (5 Jun 2020)

That level of Chloride shouldn’t be a problem, I used SaltyShrimp GH+ very successfully to remineralise before I went DIY and that’s made entirely of Magnesium Chloride and Calcium Chloride, at a GH of 6 and 150-200ppm TDS the Chloride is in excess of 100ppm.

As I said you’ve got to be careful with that calculator when translating formulas for it to calculate as Darrel pointed out that it’s easy to miss a few atoms. I should have been more careful when I posted the above solving, it was more a demonstration than the direct calculation.


----------



## Wookii (5 Jun 2020)

dw1305 said:


> Hi all, Right idea, wrong answer, you got a bit carried away with the hydrogen atoms (H), and a lot less carried away with the oxygen.
> 
> I think it should be: CaCl2.6H2O = 1 * Ca, 2 * Cl, 12 * H, 6* O so 40 + 71 + 12 + 96 = 219
> 
> ...



Thanks Darrel - this is a veritable minefield!

So a mix for a 75 litre water change with RO water is:

7.73g Calcium Chloride 
6.0g Magnesium Sulphate
75 litres RO Water
(+ Citric acid to 2-3Ph)

This will yield (according to James Planted Tank) 5 dGH. If I want to target 6 dGH, i need:

9.28g Calcium Chloride (CaCl.6H2O)
7.2g Magnesium Sulphate (MgSO4)
75 litres RO Water
(+ Citric acid to 2-3Ph)

That should give me Ca:Mg 3:1, and 6dGH?

For the dKH additive, I just mix 5.4g Potassium Carbonate (KHCO3) to the 75 litre RO mixture for 2 dKH?

 . . . I think I'm going to need a lie down! lol


----------



## Wookii (5 Jun 2020)

X3NiTH said:


> That level of Chloride shouldn’t be a problem, I used SaltyShrimp GH+ very successfully to remineralise before I went DIY and that’s made entirely of Magnesium Chloride and Calcium Chloride, at a GH of 6 and 150-200ppm TDS the Chloride is in excess of 100ppm.
> 
> As I said you’ve got to be careful with that calculator when translating formulas for it to calculate as Darrel pointed out that it’s easy to miss a few atoms. I should have been more careful when I posted the above solving, it was more a demonstration than the direct calculation.



Thanks @X3NiTH - that good to read - I was going to use Salty Shrimp initially, and wondered exactly what was in it.

Don't worry on the calculator - its actually a very good tool, but clearly still a bit above my pay grade.


----------



## X3NiTH (5 Jun 2020)

For remineralising RO for use as replacement water you don’t need to add Citric Acid unless you are making a concentrate and using carbonate compounds (CaCO3, MgCO3, KCO3).


----------



## Zeus. (5 Jun 2020)

X3NiTH said:


> I always found towards the end of use of a 500ml bottle of DIY AIO that there was always a milky brown precipitate, the things that could affect the mixture in the bottle are storage temperature, exposure to light and evaporation



So whats the comercail AIO solution


----------



## dw1305 (5 Jun 2020)

Hi all, 





Wookii said:


> Thanks Darrel - this is a veritable minefield!


The main issue is usually the <"water of crystallization">, it can make a lot of difference to the RMM and percentage of the nutrients.  

If I'm working it out for some-one else I usually check via "Rotala butterfly". I can remember the atomic weights of most of the common elements, and I'm not too bothered about precision, so usually if it is just for me I use a bit of mental "guesstimation".

It is useful to know the valency of the elements. Because calcium has a valency of two (Ca++ as an ion) you need to add two chlorine atoms (Cl- as an ion) to balance the equation and that gives you Ca(Cl)2.

cheers Darrel


----------



## Wookii (5 Jun 2020)

X3NiTH said:


> For remineralising RO for use as replacement water you don’t need to add Citric Acid unless you are making a concentrate and using carbonate compounds (CaCO3, MgCO3, KCO3).



I am making a concentrate to auto-dose into a mixing container for automated water changes.

The Citric acid was discussed above - check post #31 onwards regarding preventing precipitation.


----------



## X3NiTH (5 Jun 2020)

I know your trying to make a concentrate but you’ve swapped out using CaSO4 for CaCl alongside MgSO4 and so long as the concentrate is below the solubility threshold for CaSO4 precipitation then it will all stay in solution without the need to acidify.

I started preparing to going down the liquid concentrate remineralisation strategy last year but I got distracted by setting up a marine system which has its own set of challenges related to similar issues when it comes to DIY where a two part brine mixture has the most stability (the concentrate holding the MgSO4 is at the threshold for solubility and the mixture I found needs warmed to 30c to get it all into solution, ATI Absolute Ocean).

The reason I prepared to go liquid remineralisation was because of reactivity between salts.

Part A is usually unreactive though I have seen occasional off white discolouration in the powder here and there but it fully goes into solution for 25L  (with help).









Part B is where the problems arose.













As you can see it’s turned into an amorphous crystal mass which is insoluble in water, it happened because CaNO3 and MgNO3 are exceptionally hygroscopic and probably absorbed any water vapour in the bag then melting with the phosphate forming an Apatite.

Not quite got round to planning the solution to partB yet but I’ll be putting the Nitrates, Sulphates and Chlorides in one concentrate and keeping the Phosphate separate (probably add it to my liquid bio carbon dose).

My recipe above was to simulate Karst water.


----------



## Wookii (5 Jun 2020)

X3NiTH said:


> I know your trying to make a concentrate but you’ve swapped out using CaSO4 for CaCl alongside MgSO4 and so long as the concentrate is below the solubility threshold for CaSO4 precipitation then it will all stay in solution without the need to acidify.
> 
> I started preparing to going down the liquid concentrate remineralisation strategy last year but I got distracted by setting up a marine system which has its own set of challenges related to similar issues when it comes to DIY where a two part brine mixture has the most stability (the concentrate holding the MgSO4 is at the threshold for solubility and the mixture I found needs warmed to 30c to get it all into solution, ATI Absolute Ocean).
> 
> ...



Thanks. So as far as I can tell from Google the solubility threshold of Calcium Chloride Hexahydrate is 49.4g/100ml, and for MgSO4 is 36g/100ml.

Given I’m looking to dose 9.3g and 7.2g respectively per water change, if I aim to dissolve those in, let’s say, a 50ml solution with RO water per dose. Do you think I won’t need to add Citric acid to prevent precipitation?

So I could store a 5 litre mix with 930g of  CaCl and 720g of MgSO4 (so enough for 100
days worth of doses @50ml each) without any precipitation issues?

Would you recommend adding potassium sorbate to that to act as a preservative?


----------



## Witcher (5 Jun 2020)

Wookii said:


> Thanks. So as far as I can tell from Google the solubility threshold of Calcium Chloride Hexahydrate is 49.4g/100ml, and for MgSO4 is 36g/100ml.
> 
> Given I’m looking to dose 9.3g and 7.2g respectively per water change, if I aim to dissolve those in, let’s say, a 50ml solution with RO water per dose. Do you think I won’t need to add Citric acid to prevent precipitation?


I'm nearly sure CaCl in reaction with citric acid will form HCl and calcium citrate, which could precipitate due to low solubility. But I'm not a chemist, so maybe someone else could shed more light on this.


----------



## X3NiTH (6 Jun 2020)

Wookii said:


> So I could store a 5 litre mix with 930g of CaCl and 720g of MgSO4 (so enough for 100
> days worth of doses @50ml each) without any precipitation issues?



No the Solubility of CaSO4 is 0.2g/100ml, it’s likely at those ratios in a concentrate that you’ll end up with a MgCl ion solution and CaSO4 precipitation regardless of acidification (I think from what I have read is that you only get a 12% increase in solubility @pH 2.5) Just keep Calcium compounds (Chlorides/Nitrates) away from Sulphate compounds in concentrated solutions.


----------



## X3NiTH (6 Jun 2020)

Witcher said:


> I'm nearly sure CaCl in reaction with citric acid will form HCl and calcium citrate, which could precipitate due to low solubility. But I'm not a chemist, so maybe someone else could shed more light on this.



Calcium, always a troublemaker in solution!


----------



## X3NiTH (6 Jun 2020)

Just to point out that I did say above in post #54 that I would mix CaNO3 with MgSO4 as a concentrate, the maximum precipitation at these ratios in a solution at concentration above the saturation point for CaSO4 solubility would be the loss of less than 1 ppm of Calcium due to only having 1ppm of SO4 in the recipe, it’s an acceptable loss and the precipitate is easily filtered out if necessary.


----------



## Wookii (6 Jun 2020)

X3NiTH said:


> No the Solubility of CaSO4 is 0.2g/100ml, it’s likely at those ratios in a concentrate that you’ll end up with a MgCl ion solution and CaSO4 precipitation regardless of acidification (I think from what I have read is that you only get a 12% increase in solubility @pH 2.5) Just keep Calcium compounds (Chlorides/Nitrates) away from Sulphate compounds in concentrated solutions.



Thanks, so it isn’t workable then even with Calcium Chloride then! If we have to adjust to solubility thresholds for CaSO4 it means dosing litres at a time, which isn’t practical - I feel like I’m going around in circles 

I note your point above in using CaNO3, but it’s hard to get hold of and using it appears to add too much nitrate (>50ppm).

Ok so one last ditch attempt before I give all this up as a bad job - I can only see two possible options:

a) keep CaCl and MgSO4 concentrated solutions in separate containers. Problem is insufficient dosing heads available on my doser, so can either of those solutions have the Potassium Bicarbonate (KHCO3) added for the KH adjustment so that doesn’t have to be separate also?

Or 

b) switch MgSO4 for MgCl (Magnesium Chloride), but then I’m adding no Sulphate other than via the MgSO4 in the macro dose every other day, and pushing the chloride levels higher (though that might not be an issue)?


----------



## Wookii (6 Jun 2020)

@X3NiTH and @dw1305 Any thoughts on the above two options guys? From a quick Googles it looks as though Option a wont work and will precipitate either Calcium Carbonate or Magnesium Carbonate.

So how about option b and just use Calcium Chloride and Magnesium Chloride? I wonder if that's what Salty Shrimp use if it results in such high Chloride levels?


----------



## X3NiTH (6 Jun 2020)

Option B

There’s nothing wrong about the chloride levels for Salty Shrimp GH+, the mix is blended so there is only GH and no KH (Salty do many more blends that include KH), it’s no barrier for good plant growth.






How many dosing channels can you dedicate to this, if you have a four part doser specifically for this then it should be fairly easy to design a more nuanced custom blend to reduce the Chloride and use other salts but also keep separate the reactive elements in concentrate.


----------



## Wookii (6 Jun 2020)

X3NiTH said:


> How many dosing channels can you dedicate to this, if you have a four part doser specifically for this then it should be fairly easy to design a more nuanced custom blend to reduce the Chloride and use other salts but also keep separate the reactive elements in concentrate.



I have a four pump dosing unit, but two will be used for micro and macro mixes, so I effectively have two spare to allocate to the RO mixing.

Everyone raves about the Salty Shrimp stuff, so the Chloride can't be an issue as you say.

So I would be okay to have a mixed Calcium Chloride and Magnesium Chloride concentrate on one pump, and a Potassium Bicarbonate concentrate on the other?

If so, then its back to the drawing board to work out how much of each of the CaCl and MgCl2 to add to the concentrate to give the target 3:1 ratio and how concentrated the solution can be without causing issues?


----------



## X3NiTH (6 Jun 2020)

No, you have three pumps available because you are missing a trick, your daily replacement water is your macro dose and it’s 75L in volume so you can carefully blend a mix to front load all the macro.

That’s what my blend does!


----------



## Wookii (6 Jun 2020)

X3NiTH said:


> No, you have three pumps available because you are missing a trick, your daily replacement water is your macro dose and it’s 75L in volume so you can carefully blend a mix to front load all the macro.
> 
> That’s what my blend does!



Hmm, interesting idea - I was thinking about how I would tackle the effect of the MgSO4 in the macro mix on the overall tank Gh.

So my macro mix is the standard APFUK, so the rest of the mix is Potassium Nitrate (KNO3) and Potassium Phosphate (K2NO4).

So there’d be no issues with dosing macros every day - i.e. the same day as micros?


----------



## X3NiTH (8 Jun 2020)

No problem doing the same day if you keep them separated by time. I’ll be assuming you will be performing the water change after lights out because if your dosing co2 it would not be beneficial to do this mid photoperiod (unless your change water is pre loaded with co2), the macro will always be there at a background level, that’s the idea anyway, how much macro you need to add to the water change (or modify how the water is reconstituted) may vary depending whether you see accumulation of nutrients (like nitrate) over time or depletion (either through observation or testing, whichever floats your boat). Dose the micro before lights on.


----------



## Wookii (8 Jun 2020)

X3NiTH said:


> No problem doing the same day if you keep them separated by time. I’ll be assuming you will be performing the water change after lights out because if your dosing co2 it would not be beneficial to do this mid photoperiod (unless your change water is pre loaded with co2), the macro will always be there at a background level, that’s the idea anyway, how much macro you need to add to the water change (or modify how the water is reconstituted) may vary depending whether you see accumulation of nutrients (like nitrate) over time or depletion (either through observation or testing, whichever floats your boat). Dose the micro before lights on.



Well, I can schedule the water change to be completed anytime of course, but on my current 60 litre tank I schedule it for the morning about three hours before lights on. That only really came about so I could visually check the auto-water change process on a weekend morning to check it was working properly, and also the fact that the tank is in my son's bedroom so a water change at night would be no good, as the airstone and solenoids do make some noise.

The new tank will be in the main lounge so the noise is not so much of an issue.

It will presumably take the RO unit several hours to generate the 75 litres of RO water, so that could be done over night, and then released to the tank for the water change at, say 8am. If I then wait until midday to dose the micros, would that be long enough?  If I'm effectively dosing macro's daily, then I may as well split the micro dose, and do that daily also - it should create more consistency than the 2 day yo-yo effect - thats part of the reason I do daily water changes for better day-to-day consistency.

So, in terms of dosing container I need:


Calcium Chloride ( CaCl.6H2O ) - dosing 9.3g per water change in 30ml of RO water (3 litre mix of RO + 930g)
Potassium Carbonate (K2CO3) - 5.4g per water change in 10ml of RO water (1 litre mix of RO + 540g)
Macro Mix + additional Magnesium Sulphate (MgSO4) - macro mix (50ml) + 7.2g MgSO4 in 25ml RO water = 75ml daily dose (7.5 litre mix of RO + macro mix + 720g MgSO4)
(* - macro mix as per standard mixing instructions is 10ml x 3 times per week + 50% weekly water change. On my 60 litre tank I calculated previously that dosing every other day (14 day cycle) + 25% daily water change requires a dose of 20ml every two days to maintain calculated EI target levels. Hence daily dosing for 300 litres equates to: (20ml x 300/60)/2 = 50ml

I will of course test all this by making up a small quantity of the three mixtures and dosing to a container of RO to see if it produces the right Gh and Kh. I also need to go back and re-run my calculations for the macro mix conversion from standard EI procedure to daily dosing and daily water changes. However, that aside, is there anything that looks amiss with any of the above?

@Zeus. having had a quick look at your current version of the spreadsheet, am I right in thinking it doesn't have the ability to adjust for daily water changes and daily dosing?


----------



## Wookii (8 Jun 2020)

Another thought. If I'm adding 7.2g MgSO4 per 75 litre daily water change, is there any point in also including MgSO4 in the macro mix, which is adding approx 3g of MgSO4 per day? (which will also increase the Gh from the target of 6dGH I'm shooting for)?


----------



## Zeus. (8 Jun 2020)

Wookii said:


> having had a quick look at your current version of the spreadsheet, am I right in thinking it doesn't have the ability to adjust for daily water changes and daily dosing?



If the weekly WC total WCs is less than the Tank volume - yes it will work

Daily dosing - yes



Wookii said:


> If I'm adding 7.2g MgSO4 per 75 litre daily water change, is there any point in also including MgSO4 in the macro mix, which is adding approx 3g of MgSO4 per day?



which the calculator also does as it gives the dry dosing weight for MgSO4- so if its says dose 5grams MgSO4 three times a week and your doing auto WCs then just dose 2.1gMgSO4 a day


----------



## Wookii (8 Jun 2020)

Zeus. said:


> If the weekly WC total WCs is less than the Tank volume - yes it will work
> 
> Daily dosing - yes



Technically 25% per day is more than the total tank volume, but it doesn’t work that simply, as if you consider a week in isolation each water change effectively changes out some of the water from the previous days water change. There is a cumulative effect.

The only way I was able to work it out for my 60 litre was plot out the movements each day in Excel and then use Goal Seek to find the daily dose that achieved the long term equilibrium target ppm concentration in line with EI targets




Zeus. said:


> which the calculator also does as it gives the dry dosing weight for MgSO4- so if its says dose 5grams MgSO4 three times a week and your doing auto WCs then just dose 2.1gMgSO4 a day



Again that doesn’t work as it doesn’t work linearly, each water change removes a proportion of doses from the previous day(s). When I worked it out for my 60 litre, I had to increase my alternate day doses from 12ml to 20ml to account for the daily water changes, and the fact that the auto doser can only work on a 14 day schedule (i.e. no rest day).


----------



## X3NiTH (9 Jun 2020)

Wookii said:


> Another thought. If I'm adding 7.2g MgSO4 per 75 litre daily water change, is there any point in also including MgSO4 in the macro mix, which is adding approx 3g of MgSO4 per day? (which will also increase the Gh from the target of 6dGH I'm shooting for)?



Not really but you can divide your Macro dose elements amongst the remineralisation concentrates.

Of the Macro Elements these are the compounds I would use either in replacement or supplement to each other when targeting a specific GH and KH. Off the top of my head I have grouped the compounds so in solution they have a low chance of precipitive reactivity with each other at concentration.

Group A -
Calcium Chloride
Magnesium Chloride
Potassium Chloride
Calcium Nitrate
Magnesium Nitrate
Potassium Nitrate

Group B -
Calcium Sulphate
Magnesium Sulphate
Potassium Sulphate

Group C -
Potassium Carbonate
Potassium Bicarbonate
Potassium Phosphate

Group D - (requires preparation to increase solubility)
Calcium Carbonate
Magnesium Carbonate

How much you use in combination with each other depends on what element ratios and ppm nutrient levels you want to stay close to whilst targeting a specific GH and KH.

If you have all the base Micro Elements as Compounds then you can add those to their respective groups (A and B) to eliminate having to make a separate micro mix, you would still need to dose Iron separately though.

Dosing Micro in the dark gives plants a chance to uptake a bigger dose of Iron before the lights come on which will photodegrade the associated chelate (APFUK Micro is EDTA) dropping out the Iron. The other advantage to dosing before lights on is that with your CO2 injection profile the pH of the water should hopefully be below neutral and if preferable be around pH6.5 so that EDTA doesn’t break down further in above neutral conditions.


----------



## Wookii (9 Jun 2020)

X3NiTH said:


> Not really but you can divide your Macro dose elements amongst the remineralisation concentrates.
> 
> Of the Macro Elements these are the compounds I would use either in replacement or supplement to each other when targeting a specific GH and KH. Off the top of my head I have grouped the compounds so in solution they have a low chance of precipitive reactivity with each other at concentration.
> 
> ...



Thanks @X3NiTH that’s great stuff.

The other two macros I have (APFUK Starter Kit) are Potassium Nitrate and Potassium Phosphate.

So based on your list then, my three bottles need to be:

1. Calcium Chloride + Potassium Nitrate
2. Magnesium Sulphate
3. Potassium Carbonate + Potassium Phosphate

My micros are the APFUK premix, so I’ll keep those as is.

Thanks for the points on the iron. I have had previous iron issues on my current tank which just uses tap water, possibly because the hard water pushes the Ph up to around 7.2-7.4 at night, so I have been supplementing the micro mix with DTPA iron which fixed my issues.

I’m hoping with RO on the new tank, along with a KH of around 3 (likely buffered down a little by soil etc) it will stay below Ph7?

I also wasn’t aware that the plants would uptake and store nutrients during lights out, so that’s good know.


----------



## Wookii (20 Jun 2020)

@dw1305 and @X3NiTH , I’m trying to buy the Calcium Chloride, and can’t seem to get hold of the Hexahydrate (well I can but it’s £22 for 250g).

I can get the Dihydrate version of course, but does that change all the calculations above, or does the Dihydrate become Hexahydrate as soon as you open the container due to absorbing atmospheric moisture?


----------



## dw1305 (20 Jun 2020)

Hi all, 





Wookii said:


> I can get the Dihydrate version of course, but does that change all the calculations above, or does the Dihydrate become Hexahydrate as soon as you open the container due to absorbing atmospheric moisture?


Yes, just buy the dihydrate (CaCl2.2H2O).  I think it will be the hexahydrate when you use it.<"The Saltwiki says"> 





> At room temperature (20ºC), the hexahydrate [Antarcticite]] is the stable phase .    having a deliquescence humidity of about 30% RH. Lowering the relative humidity at the same temperature, calcium chloride tetrahydrate forms at values below 18% RH, while dehydration to the dihydrate (sinjarite) occurs at 9% RH,


I assume they store the compound at low humidity and that is why you buy it as the dihydrate.

The maths is quite simple if you want to work out the difference. The CaCl2 remains the same, so you have the RAM of calcium (Ca = 40.1) and then you need to add the chlorine (Cl = 35.5), hydrogen (H = 1) and oxygen (O = 16) together to give you an RMM of 147 for CaCl2.2H2O and an RMM of 219 for CaCl2.6H2O.

You then just need to divide 147/219 = 0.67. So if you needed to add 10 grams of the hexahydrate, you need to add 6.7g  of the dihydrate to give you the same amount (ppm/mg/L) of calcium.  Along the same lines the percentage calcium for the dihydrate is 40/147 = 27.2% and for the hexahydrate 40/219 = 18.3%.

cheers Darrel


----------



## X3NiTH (20 Jun 2020)

The Dihydrate should be fine, the amount of impurity will be vanishingly small when dosed in the amounts you plan (obviously you’ll need to adapt the calculation to take into account less water of crystallisation and extra element impurity).

The only elements of impurity listed by APC Pure are for 77.5% Dihydrate is Fe at <10mg/Kg, the impurity list is probably longer, Food Grade 77% Calcium Chloride Dihydrate from Intralabs has a more detailed analysis -





The Dihydrate may form Hexahydrate if left exposed in humid conditions but will still only be 77% pure whereas the Hexahydrate has more processes put upon it to reach 98% purity, hence the extra expense.


----------



## X3NiTH (20 Jun 2020)

Lol posted seconds apart!

Darrel wins he gave you the math, although he may need to adjust that though for the impurity!


----------



## dw1305 (20 Jun 2020)

Hi all,  





X3NiTH said:


> The Dihydrate may form Hexahydrate if left exposed in humid conditions but will still only be 77% pure whereas the Hexahydrate has more processes put upon it to reach 98% purity, hence the extra expense.


I didn't know that. At work it would be analytical grade, and I never use it in the tanks. 





X3NiTH said:


> Darrel wins he gave you the math, although he may need to adjust that though for the impurity!


Yes, but when I write it all down for somebody else I do all the maths, when I'm dosing the fish tank myself, I use the "_sprinkle it into your hand, tip it in the tank_" method for larger amounts, and <"_lick your finger, stick it in the salt, wash it off in the tank_"> method for smaller amounts.

cheers Darrel


----------



## Wookii (20 Jun 2020)

Thanks guys, much appreciated as always. I’ll get the salts and run some practical tests to see if I come out at the desired GH and KH.


----------



## X3NiTH (20 Jun 2020)

dw1305 said:


> I didn't know that. At work it would be analytical grade, and I never use it in the tanks.



The cheapest source of Calcium Chloride would be as a byproduct of the Solvay process to produce Sodium Carbonates, the base rock substrate (?Dolomite) will be chock full of metals and I am assuming this is being mediated by the presence of EDTA in the food grade 77% Dihydrate to chelate most of the impurities out. Wet or dry and no matter the water of crystallisation it’s still going to be a homogenous mix of things you want and don’t want (and as long as they are small numbers and not harmful to the environment probably not worth mentioning.

The analytical grade stuff may possibly be made with pure CaCO3 and HCl for the Molar solutions.



dw1305 said:


> when I'm dosing the fish tank myself, I use the "_sprinkle it into your hand, tip it in the tank_" method for larger amounts, and <"_lick your finger, stick it in the salt, wash it off in the tank_"> method for smaller amounts.



Yeah I have to remind myself not to do this for topping up Nitrates and Phosphate after having a hand in the Marine Tank that houses Palythoas!


----------



## Wookii (31 Oct 2020)

X3NiTH said:


> The cheapest source of Calcium Chloride would be as a byproduct of the Solvay process to produce Sodium Carbonates, the base rock substrate (?Dolomite) will be chock full of metals and I am assuming this is being mediated by the presence of EDTA in the food grade 77% Dihydrate to chelate most of the impurities out. Wet or dry and no matter the water of crystallisation it’s still going to be a homogenous mix of things you want and don’t want (and as long as they are small numbers and not harmful to the environment probably not worth mentioning.
> 
> The analytical grade stuff may possibly be made with pure CaCO3 and HCl for the Molar solutions.
> 
> ...



So I finally got around to testing all the theory now I have all the salts and the RO unit installed.

To test I have mix up 100ml of each of the three solutions:





In the three glasses from left to right are 100ml DI water plus:

1. CaCl2 (10.4g) + KNO3 (7.1g)
2. MgSO4 (15.0g)
3. K2CO3 (9.0g) + KH2PO4 (0.6g)

Then I dose 0.8ml to 1 litre of DI water - which is the dosing rate I’ve selected (20ml per 25 litre of RO water change).

That results in 2.5dKH and 5.0dGH which is pretty close to target given all the testing and measuring errors that are possible.

My remaining issue is the CaCl2 + KNO3 solution. As you can see from the image the solution remains cloudy, presumably suggesting a solubility issue and some of the salts in suspension rather than solution? The cloudiness eventually settles in the bottom of the glass.

As far as I can tell I’m well within the solubility range for both of these which, if Wikipedia is correct, is around 31g per 100ml for KNO3 and 74g per 100ml for CaCl2 @ 20 degrees C.

So what am I missing here @X3NiTH and @dw1305? Any ideas?


----------



## Wookii (31 Oct 2020)

Right, so I tried dissolving them separately, each in 50ml of DI water:






No clouding at all and they both dissolve easily.

Then I mixed the two solutions together:





Instant clouding - so I assume this is some sort of precipitation?

The KNO3 is actually from my APFUK starter kit, so I’ll try the KNO3 I got from APC Pure to make double sure it isn’t an issue with the APFUK stuff.


----------



## Wookii (31 Oct 2020)

Wookii said:


> The KNO3 is actually from my APFUK starter kit, so I’ll try the KNO3 I got from APC Pure to make double sure it isn’t an issue with the APFUK stuff.


And the result . . . *drum roll* . . .





. . . no clouding at all!!!

So the Potassium Nitrate from APFUK is not actually Potassium Nitrate? Perhaps they supplied Calcium Nitrate instead?

EDIT: Actually it can’t be Calcium Nitrate as that would presumably give a higher Gh?


----------



## dw1305 (31 Oct 2020)

Hi all,


Wookii said:


> My remaining issue is the CaCl2 + KNO3 solution. As you can see from the image the solution remains cloudy,


Something is wrong, three of the four constituents K+, NO3-, Cl- only form soluble salts, which means that whatever calcium (Ca++) compound is formed <"should be soluble">. Are you sure the bags aren't mixed up, if you had Ca++ and PO4--- together they would precipitate out as insoluble calcium phosphate (Ca3(PO4)2).

Edit: I see you've solved your problem.


Wookii said:


> Perhaps they supplied Calcium Nitrate instead?


Still the same issue you have nitrate, potassium and chloride ions, so there isn't an insoluble compound they could form with the calcium. "Insoluble" calcium salts we are likely to encounter are calcium sulphate (very slightly soluble), calcium carbonate (soluble in weak acids) and calcium phosphate (insoluble).

cheers Darrel


----------



## Wookii (31 Oct 2020)

dw1305 said:


> Hi all,
> 
> Something is wrong, three of the four constituents K+, NO3-, Cl- only form soluble salts, which means that whatever calcium (Ca++) compound is formed <"should be soluble">. Are you sure the bags aren't mixed up, if you had Ca++ and PO4--- together they would precipitate out as insoluble calcium phosphate (Ca3(PO4)2).
> 
> ...



I did wonder if I’d mixed up the KNO3 with the PO4 to start with but the two salts are visually very distinct, and the APFUK PO4 looks identical to the PO4 I have from APC Pure - a very fine white glistening crystalline salt vs the dull almost damp looking consistency of the APFUK KNO3.

The one difference between the APFUK KNO3 and the APC Pure KNO3 is the former was very ‘off-white’ in colour and the latter almost pure white in colour - though I can’t be sure the off-white is the result of aging/absorbing atmospheric moisture?

I’ve thrown most of the APFUK KNO3 away, but just tested the small lump I have left, and it definitely contains Nitrate:





Disclaimer before I get ostracised from the forum: I don’t use the Nitrate test routinely, just in this case to show a non-zero value with some of the APFUK KNO3 in some DI water.


----------



## dw1305 (31 Oct 2020)

Hi all,


Wookii said:


> I’ve thrown most of the APFUK KNO3 away, but just tested the small lump I have left, and it definitely contains Nitrate:
> 
> View attachment 155847
> 
> Disclaimer before I get ostracised from the forum: I don’t use the Nitrate test routinely, just in this case to show a non-zero value with some of the APFUK KNO3 in some DI water.


No you are good. This is one situation where you  can be pretty sure that the test kit will give you an accurate result, because you don't have any interfering ions or nitrite (NO2-) and you've started with DI water. The only possibility for error would be failing to mix the two reagents fully.

cheers Darrel


----------



## Zeus. (1 Nov 2020)

Which CaCL2 salt (hydrate) have you got there M8 ? pic of label/package may be helpful/insightful


----------



## Wookii (1 Nov 2020)

Zeus. said:


> Which CaCL2 salt (hydrate) have you got there M8 ? pic of label/package may be helpful/insightful


It’s this one mate from APC Pure:

https://apcpure.com/product/calcium_chloride_77_5

Edit: It’s definitely not the Hexahydrate as that’s 20x the price, so I assume it’s the Dihydrate.


----------



## Zeus. (1 Nov 2020)

Which is CaCL2.2H2O- Calcium Chloride dihydrate which has a solubility of 134.5g/100ml  
They can call it pure IMO as with it being a hydrate the 'impurity' is just H20


----------



## Wookii (12 Nov 2020)

So, I've now fully made the transition to RO water. Again, I fully appreciate that test kits are frowned upon in general terms, and I wouldn't normally use them beyond ensuring water is ammonia and nitrite free at tank start-up. However I had been using the GH and KH drip tests to ensure that my remineralised RO water is producing similar values to those I've targeted with the calculated dosing of the CaCl2, MGSO4 and K2CO3 (I had no other way to confirm the calculations worked in practice).

The RO water consistently comes out with a GH of 5.5-6 and KH or 2.5-3, which is exactly what I was aiming for with all the calculations in this thread. This is testing 25 litres of RO water which is fully dosed with remineralisation salts and daily dose of macro fert salts (KNO3, KH2PO4 and K2SO4). This RO water comes out with a TDS almost bang on 200ppm.

The anomalie that I'm encountering is when I test the actual tank water, the drip tests result in a GH of around 9-10, and a KH of around 5-6. I've done enough water changes (25% daily) now that the tap water the tank started off with should have been fully exchanged, and I have also done a number of pure RO water changes to bring the GH, KH and TDS down a little faster.

My first thought was that the fairly large amount of Sieryu stone I have in the tank, and the fact that the pH dips down to 6.1 during the CO2 period, might mean the stone is buffering the KH and GH? However when I tested the TDS on the tank last night, it came out at about 195ppm, lower than the remineralised RO water presumably due to the few changes of pure RO that I've done.

I'm happy to take it on the chin from people telling me "Test kits . . told you so . . ." but as I don't really do taking things on pure faith very well, what I'd really like to understand is what might be causing the anomalie in the drip tests. These tests seem capable on reliably confirming the approximate KH and GH of my RO water, and also confirm exactly the GH of my tap water shown on my water report. So are there some chemicals at play in the tank water that throw these tests so far out?


----------



## dw1305 (12 Nov 2020)

Hi all,


Wookii said:


> My first thought was that the fairly large amount of Sieryu stone I have in the tank, and the fact that the pH dips down to 6.1 during the CO2 period, might mean the stone is buffering the KH and GH?


Would be my guess.


Wookii said:


> The anomalie that I'm encountering is when I test the actual tank water, the drip tests result in a GH of around 9-10, and a KH of around 5-6.....However when I tested the TDS on the tank last night, it came out at about 195ppm


The TDS (conductivity) reading should be right. It is a linear scale and pretty straightforward. That is why I like conductivity as a metric, it might not be that useful, but it will be accurate.

After that It is going to depend upon what the test kits actually measure. The dKH drop test <"measures alkalinity"> via an <"acid base titration">, and I have no personal experience of their accuracy.

I've no idea how the dGH kit works, but if it produces a white precipitate? It may use soluble dilute sodium hydroxide (NaOH) to <"form insoluble Ca(OH)2 and Mg(OH)2">.

You would also potentially get aluminium and iron hydroxides formed  as well, although they wouldn't necessarily be white, and as the solution became <"more alkaline the aluminium ions would go back into solution">.


Wookii said:


> .....with the calculated dosing of the CaCl2, MGSO4 and K2CO3.  (I had no other way to confirm the calculations worked in practice).





dw1305 said:


> This is one situation where you can be pretty sure that the test kit will give you an accurate result, because ..........you've started with DI water.


But you actually know exactly how much dKH and dGH you have in your RO water, because it is *the amount you've added*, it is your standard. If the test kit numbers you've got are different? It is the test kit that is wrong.

The workings are in <"What do the three....">, derived from Larry Frank's very useful <"the Krib"> article.

cheers Darrel


----------



## Wookii (12 Nov 2020)

dw1305 said:


> Hi all,
> 
> Would be my guess.



Thanks as always Darrel.  Would the stone really release carbonates and calcium and magnesium that fast then to sustain such a large increase (doubling) of the GH and KH - bearing in mind the 25%+ daily water changes? Everything I've read seems to suggest the release is quite slow even with weekly water changes?



dw1305 said:


> The TDS (conductivity) reading should be right. It is a linear scale and pretty straightforward. That is why I like conductivity as a metric, it might not be that useful, but it will be accurate.



That was my thinking too, which is why I can't reconcile the idea that the TDS can measure the same, but the GH and KH can be double. I appreciate the fert salts will be less diluted in the tank water, and some will also be used up, but is that likely to be enough to account for the same TDS but double the Ca/Mg and Carbonates? My only conclusion then is failure of the test solutions, or rather not their failure, but possibly something else throwing them out.



dw1305 said:


> I've no idea how the dGH kit works, but if it produces a white precipitate? It may use soluble dilute sodium hydroxide (NaOH) to <"form insoluble Ca(OH)2 and Mg(OH)2">.



No, there is no precipitate, its a simple colour change (titration?) drop test kit also - one drop = 1dGH (or 0.5dGH if you double the test volume etc), keeping adding drops until the colour changes.



dw1305 said:


> But you actually know exactly how much dKH and dGH you have in your RO water, because it is *the amount you've added*, it is your standard. If the test kit numbers you've got are different? It is the test kit that is wrong.



Sorry what do you mean here? Are you saying if the test kit measures the RO water correctly, then the measurements of the tank water are also correct? if so, how do we account for the TDS being the same?


----------



## dw1305 (12 Nov 2020)

Hi all, 


Wookii said:


> Sorry what do you mean here? Are you saying if the test kit measures the RO water correctly, then the measurements of the tank water are also correct?


No, I mean you don't need to measure the RO + salts water to get a dGH, or dKH, value. You know how much of each of the salts you've added, and from there you can <"work out exactly"> what the true dGH and dKH values are.  

This is for dGH


> By definition, 1dGH = 10 mg/liter CaO
> Atomic Weight Ca = 40, O = 16, CaO = 56
> So 10 mg/liter CaO contains 40/56 *10 = 7.143 mg/liter of Ca​
> Atomic weight CaCO3 = 100
> ...


and this is for dKH


> 1dKH = 17.86 ppm CaCO3
> From above; 1dKH = 17.8575 mg/liter CaCO3. 7.143 mg/liter of this is Ca, the rest ;(17.8575-7.143)= 10.7145mg/liter CO3
> 1dKH = 10.7145 ppm CO3


For magnesium (Mg) you still have convert it to its equivalent weight in CaO, but from <"James' Planted Tank">


> 1 dGH = 7.2mg/l Ca++
> 1 dGH = 4.3mg/l Mg++
> ............
> 1.8g KHCO3 in 25 litres of water = 2 dKH
> 1.2g K2CO3 in 25 litres of water = 2 dKH





Wookii said:


> how do we account for the TDS being the same?


The TDS value is almost certain to be accurate. It maybe that K+, PO4---, Mg++ and NO3- etc ions have been taken up by the plants and the additional TDS is from Ca++ and 2HCO3- ions that have gone into solution from the stone, but I'm dubious.

cheers Darrel


----------



## Wookii (12 Nov 2020)

dw1305 said:


> Hi all,
> 
> No, I mean you don't need to measure the RO + salts water to get a dGH, or dKH, value. You know how much of each of the salts you've added, and from there you can <"work out exactly"> what the true dGH and dKH values are.



Ah, I see what you mean, thanks Darrel. yes, sorry, the testing of the remineralised RO is as more of a system test as much anything else - remember I'm dosing from pre-mix solutions via an auto-doser, rather than dry salts straight into the RO water, so a few places where things can go wrong (me messing up the mixes, dosing the incorrect proportions, doser drifting on calibration etc)..



dw1305 said:


> The TDS value is almost certain to be accurate. It maybe that K+, PO4---, Mg++ and NO3- etc ions have been taken up by the plants and the additional TDS is from Ca++ and 2HCO3- ions that have gone into solution from the stone, but I'm dubious.
> 
> cheers Darrel



I'm dubious too. For simplicity, lets just consider the dGH, and assume the rocks are just giving up calcium carbonate, so if I've understood your conversions correctly, a 5dGH increase would be 17.86mg CaCO3 x 5 = 89.3mg per litre. Would be 89.3ppm contribution to TDS alone? 

So in my 96 litre tank, that would would be 8.57 grams (89.3mg x 96l) of CaCO3 being released every few days? That seems a lot.


----------



## dw1305 (12 Nov 2020)

Hi all,


Wookii said:


> Would be 89.3ppm contribution to TDS alone?


Unfortunately the "ppm" value for TDS and the ppm for from the salt addition aren't the same unit, mainly because different ions conduct different amounts of charge. The 100 microS ~ 64ppm TDS is where the predominant salts are Ca++ and HCO3-. If your main salt is NaCl (Na+ Cl-) then the conversion is 100 microS ~ 50ppm TDS.


Wookii said:


> remember I'm dosing from pre-mix solutions via an auto-doser, rather than dry salts straight into the RO water, so a few places where things can go wrong (me messing up the mixes, dosing the incorrect proportions, doser drifting on calibration etc)..


I'd forgotten that, and that makes sense.


Wookii said:


> So in my 96 litre tank, that would would be 8.57 grams (89.3mg x 96l) of CaCO3 being released every few days? That seems a lot


My thought as well, you pretty soon wouldn't have any rock left.

cheers Darrel


----------



## Zeus. (12 Nov 2020)

Wookii said:


> CaCl2, MGSO4 and K2CO3 .
> 
> This is testing 25 litres of RO water which is fully dosed with remineralisation salts


How much of each are you adding per 25l ?


----------



## Wookii (12 Nov 2020)

Zeus. said:


> How much of each are you adding per 25l ?



Each respective 2.5 litre container has 288g CaCL2, 375g MgSO4 and 225g of K2CO3.

Each 25 litre RO water change gets a 20ml dose of each, so 2.3g CaCl2, 3.0g MgSO4 and 1.8g K2CO3.


----------



## Zeus. (13 Nov 2020)




----------



## Wookii (13 Nov 2020)

Zeus. said:


> View attachment 156385
> View attachment 156386



Thanks mate, that confirms all the previous calc's pretty much exactly, and also what I measure the re-mineralised RO water at using the drip tests.

Now I'd just like to figure out what's going on in tank.

I'm going to give it another week or two of just carrying on with the daily water changes as-is at the pre-determined dosing levels and then check again to see if the GH and KH has stabilised. 

At that point if it hasn't I'm unsure of the way forward to determine if the test kits are at fault, or if indeed increases in GH and KH are happening in tank. I really need to be sure before I take any measures against reducing the reminseralisation salts added to the RO mix, for fear of making the water too soft.


----------



## Zeus. (13 Nov 2020)

Wookii said:


> that confirms all the previous calc's pretty much exactly,


Good, it also does another level on 'checking' on our calculations as well


----------



## Wookii (13 Nov 2020)

Zeus. said:


> Good, it also does another level on 'checking' on our calculations as well



Do you know when the calculator will be released yet - will be good to have a play with it?

Incidentally I didn't realise quote how much K was being added by the K2CO3 (!) - we may need to revisit the K2SO4 dosing included on the calculator you sent my via PM?


----------



## Zeus. (13 Nov 2020)

Wookii said:


> Do you know when the calculator will be released yet


Soon, I would be more definitive, but we have to get it passed off by our experts first also 😬, we are hoping before Christmas 2020 all the same as we are getting down to the finer details ATM.


----------



## dw1305 (13 Nov 2020)

Hi all,


Zeus. said:


> Good, it also does another level on 'checking' on our calculations as well


Was it potassium carbonate (K2CO3), rather than potassium bicarbonate (KHCO3)? If so it makes the dKH = 1.5 and 40.7 ppm K.

Doing the dGH "long hand" (using the values  from <"James' Planted Tank">, and assuming the two salts are the stable hydrates (CaCl.6H2O) and Mg.SO4.7H2O) I get:

Ca = 2.34 dGH and Mg = 2.75 dGH, so 5.1 dGH. When I  get a moment I'll go through it properly via the calculations <"in the Krib">.

cheers Darrel


----------



## Wookii (13 Nov 2020)

dw1305 said:


> Hi all,
> 
> Was it potassium carbonate (K2CO3), rather than potassium bicarbonate (KHCO3)? If so it makes the dKH = 1.5 and 40.7 ppm K.
> 
> ...



Good spot Darrel - it's a good job you are on point lol . . .  yes, its K2CO3 I'm adding, Potassium Carbonate. https://apcpure.com/product/Potassium_Carbonate_Anhydrous_99_ACS

Edit: I based the dosing for that on the James Planted Tank page, which states:



> 1.5g NaHCO3 in 25 litres of water = 2 dKH
> 1.8g KHCO3 in 25 litres of water = 2 dKH
> 1.2g K2CO3 in 25 litres of water = 2 dKH



So should my 1.8g dose of K2CO3 not yield 2dKH / 1.2 x 1.8 = 3dKH?


----------



## dw1305 (13 Nov 2020)

Hi all,


Wookii said:


> So should my 1.8g dose of K2CO3 not yield 2dKH / 1.2 x 1.8 = 3dKH?


I like this checking thing, and it should *3 dKH.*

So apologies, that was me using 1.8g = 1 dKH, rather than 1.8g = 2 dKH.

cheers Darrel


----------



## Wookii (23 Nov 2020)

dw1305 said:


> Hi all,
> 
> Would be my guess.
> 
> ...



OK, so back on this one Darrel, I've been reading through some of the links you gave, though most of the real chemistry is beyond me, and the whole KH/alkalinity discussion appears to be Alice's 'rabbit hole', so I don't want to fall down that too far!

After another week of water changes, I'm still consistently measuring a KH (alkalinity) of around double what I'm adding to the RO mix, and a GH around 1.5 times. Having now read around a number of other forums, I've seen a number of other similar experiences when using large amounts of Seiryu stone. Since the whole point of me going to the effort and expense of the RO system, was to maintain soft water for soft water fish species - purely to give them the best possible environment and care, I need to establish a practical way forward, and chalk up (no pun intended lol) the extensive use of stone containing calcium carbonate as a 'schoolboy error' (next time I'll be using lava rock!).

So, at risk of wearing you a little thin on this subject, can I pose some more questions?

1. If the KH measures alkalinity rather than pure carbonate content, do we actually care - from a practical sense - about the quantity of carbonates? What I mean by that is, if the aquarium water is obtaining additional alkalinity from somewhere, in terms of providing a healthy aquarium, do we care what it is comprised of, or simply that it exists? If not, it would seem a practical approach would be to simply cease dosing K2CO3 completely, which should (in theory) mean the aquarium maintains an alkalinity of around 3dKH on its own? Are there any risks in that approach?

2. If we believe that the rock is the main culprit of the increasing GH, Is it safe to assume that the difference in dGH will be appearing mainly if the form of Calcium (I assume there is no practical way to test this)? If so, it would appear that a practical solution would be to reduce the dosing of CaCL2 by half (or more if necessary) to reach the desired dGH?

3. From a fish care perspective, is all this effort worth while - will the fish actually be happier, healthier and longer lived in the softer water? Also, my only reason for trying to maintain a GH of around 7 is so the shrimp have sufficient Calcium in the water column for moulting - is this a valid objective also, or should I just go softer on the GH (perhaps not dosing CaCl2 at all) and supplement with calcium rich foods?


----------



## dw1305 (23 Nov 2020)

Hi all, 


Wookii said:


> f not, it would seem a practical approach would be to simply cease dosing K2CO3 completely, which should (in theory) mean the aquarium maintains an alkalinity of around 3dKH on its own?





Wookii said:


> If the KH measures alkalinity rather than pure carbonate content, do we actually care - from a practical sense - about the quantity of carbonates?





Wookii said:


> If we believe that the rock is the main culprit of the increasing GH, Is it safe to assume that the difference in dGH will be appearing mainly if the form of Calcium (I assume there is no practical way to test this)? If so, it would appear that a practical solution would be to reduce the dosing of CaCL2 by half (or more if necessary) to reach the desired dGH?


If the "extra" dKH is from the dissolution of limestone (CaCO3), then you don't need the potassium carbonate (K2CO3), but you should also have an equal addition of dGH (Ca++) and dKH (2HCO3-) ions.  

I might try reducing the calcium chloride hexahydrate (CaCl2.6H2O). In terms of measuring the calcium content of the water unfortunately it is <"Flame photometry, AAS or ICP">.  What does the conductivity (TDS) meter say? Is the value rising?


Wookii said:


> and supplement with calcium rich foods?


Give it a go. 


Wookii said:


> will the fish actually be happier, healthier and longer lived in the softer water?


That is just an unknown. I don't tend to muck about too much with water chemistry, just because I know I'm too lazy to be bothered with it long term.  I know that our rain-water varies between about 30 microS and 160 microS, and is usually somewhere around 120 microS mark. I just work from them, it suits soft-water fish, but not black water ones, and it isn't really hard enough for Cherry Shrimps. I have a hard, high quality tap supply, and access to DI water, but my main aim is just to use 100% rainwater. 

cheers Darrel


----------



## Wookii (23 Nov 2020)

dw1305 said:


> If the "extra" dKH is from the dissolution of limestone (CaCO3), then you don't need the potassium carbonate (K2CO3), but you should also have an equal addition of dGH (Ca++) and dKH (2HCO3-) ions.



Thats the big 'if' though isn't it. Does it matter if the extra dKH (I guess we should really say alkalinity) isn't from CaCO3, and instead is from something else (phosphates, silicate, nitrates etc - as per the James's Planted Tank page). In that case am I still okay to not dose any carbonate?



dw1305 said:


> I might try reducing the calcium chloride hexahydrate (CaCl2.6H2O). In terms of measuring the calcium content of the water unfortunately it is <"Flame photometry, AAS or ICP">.  What does the conductivity (TDS) meter say? Is the value rising?



It is yes, the TDS is up to around 250-275ppm, versus a consistent TDS of 200ppm in the RO mix, though again I can't be sure that is CaCO3 of course, and not just because the filter is due a clean etc. 



dw1305 said:


> Give it a go.



I probably will, I'm just nervous of losing or causing issues my established Bloody Mary colony.



dw1305 said:


> That is just an unknown. I don't tend to muck about too much with water chemistry, just because I know I'm too lazy to be bothered with it long term.  I know that our rain-water varies between about 30 microS and 160 microS, and is usually somewhere around 120 microS mark. I just work from them, it suits soft-water fish, but not black water ones, and it isn't really hard enough for Cherry Shrimps. I have a hard, high quality tap supply, and access to DI water, but my main aim is just to use 100% rainwater.
> 
> cheers Darrel



I don't have access to the rainwater - though I appreciate that's a daft thing to say, what I mean is I don't have the facilities/space to store it in sufficient quantities and re-routing downpipes would be traumatic at best, and my tap water is hard which is why I've gone down the RO route. If/when we move house, I do plan to move to rainwater if I can build it in.

Have you not been able to keep Cherry shrimp in your tanks then?


----------



## dw1305 (23 Nov 2020)

Hi all,


Wookii said:


> It is yes, the TDS is up to around 250-275ppm, versus a consistent TDS of 200ppm in the RO mix


That sounds pretty definitively it is the rock, and they are Ca++ and HCO3- ions.


Wookii said:


> though again I can't be sure that is CaCO3 of course, and not just because the filter is due a clean etc.


That is the useful thing with conductivity, it is just a measure of ions.

When that number goes up, you have more ions in solution they haven't been shuffled around, they are new ions. You haven't added any more salts, so it is a salt source in the tank, which is slowly going into solution.  Slow dissolution is usually indicative of <"limited solubility in a buffered system">, which is what you have here.  


Wookii said:


> Have you not been able to keep Cherry shrimp in your tanks then?


I kept them for a couple of years successfully, and I used them as a <"supplementary food for the _Apistogramma_">. I had a more black-water tank at the time (I had some <"_Parosphromenus _Bintan_"_)">  and that tank was always too soft for any snails or Cherry shrimps.  I noticed that my main colony was shrinking one winter, but I didn't think too much about it.

Eventually <"all I saw were very occasional shrimps"> and I noticed that I had very few Red Ramshorn snails left, and the remaining ones I had were all small, white and paper thin. At this  point I measured the conductivity and it was about 60 microS.

My shrimp population never recovered, probably because all the remaining ones were male.

cheers Darrel


----------

