GH+KH RO Reminiralzation Product Help.

[Wookii]

@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]

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]

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]

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]

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]

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]

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:

1. Calcium Chloride ( CaCl.6H2O ) - dosing 9.3g per water change in 30ml of RO water (3 litre mix of RO + 930g)
2. Potassium Carbonate (K2CO3) - 5.4g per water change in 10ml of RO water (1 litre mix of RO + 540g)
3. 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]

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.]

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

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]

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

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]

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]

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.

🙂

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]

@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]

Hi all,

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]

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]

Lol posted seconds apart!

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

🙂

 

[dw1305]

Hi all,

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.

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]

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]

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.

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]

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.



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!

🙂

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?