# Remineralising RO



## PeteA (25 Oct 2011)

After just spotting Darren's link in this topic: http://www.ukaps.org/forum/viewtopi...&sid=6fafeadda99c1640c331288e6c31497a#p185647 I was curious as to how many people use a DIY method of remineralising their RO water and what sort of amounts they use.  I'm slowly getting my new tank together (journal to follow soon) and would like some of the more fussy shrimp so lots of investigation on the best way of getting the water "ideal".

And yes I know a lot of people slice their RO with tap water - the tap water from my tap isn't that great so I don't want to risk it.


----------



## Matt Warner (25 Oct 2011)

Hi, why is your tap water so bad? Tap water contains many of the nutrients which plants need and it's a heck of a lot cheaper than RO. Is your tap water very hard and alkaline?


----------



## wearsbunnyslippers (25 Oct 2011)

ime stable water parameters are better than perfect ones...

you will spend a lot of time and money increasing gh, decreasing, softening, RO, etc. when if you can just get in the ballpark, even some of the fussy shrimp ( excluding sulawesi ) will be fine..

using a substrate like aquasoil is a good start!


----------



## PeteA (26 Oct 2011)

Matty1983 said:
			
		

> Hi, why is your tap water so bad? Tap water contains many of the nutrients which plants need and it's a heck of a lot cheaper than RO. Is your tap water very hard and alkaline?



I just found my tap water fluctuates a lot and since changing over to RO my fish and shrimp are a lot more relaxed and active.


----------



## PeteA (26 Oct 2011)

wearsbunnyslippers said:
			
		

> ime stable water parameters are better than perfect ones...
> 
> you will spend a lot of time and money increasing gh, decreasing, softening, RO, etc. when if you can just get in the ballpark, even some of the fussy shrimp ( excluding sulawesi ) will be fine..
> 
> using a substrate like aquasoil is a good start!



My thought's exactly on stable water which is why I don't use my tap water.  I currently use Tropic ReMineral with no other additives, but it struck me reading the above that it would be cheaper and perhaps give better parameters doing it diy, which is why I wondered how other people did there remineralisation.


----------



## hotweldfire (26 Oct 2011)

Yeah, have been wondering about this myself recently. Especially after I read an article I think I found linked from this forum by a guy who made his living doing water tests and had done a bunch on aquarium shops. Said most tanks had shed loads of salt in them and that most commercial remineralisation products have a high level of sodium in them.

I cut with a bit of tap but as far as I know my tap is stable. However, I also dose EI in my main tank and have been wondering if this is all I need. I.e. surely there is enough calcium and magnesium etc in EI mixes for what the fauna need? Maybe even in TPN? In addition I am concerned about the build up of all of this which is exacerbated by the use of the tap water. My TDS just after a 40% water change (but including 1/5 the weekly dose of ferts) is around 170. A week later it is 350+.

Maybe just going pure RO is fine?


----------



## dw1305 (28 Oct 2011)

Hi all,


> Said most tanks had shed loads of salt in them and that most commercial remineralisation products have a high level of sodium in them.


 I think this will be true for a lot of shops where they still routinely add "therapeutic" salt. I also think this is true of a lot of commercial mixes. We had an answer, on another forum, from "Kent", where they said their RO re-min salt mix mirrored the salt levels in fishes and contained "carbonic acids and monosodium salts". 



> They also supplied an ingredient list:
> "Kent pH Stable"
> Chemical                                          percent
> Sodium bicarbonate                             <90
> ...


So basically sodium bicarbonate ("bi-carbonate of soda"), and sodium carbonate ("washing soda"), both of which will increase the GH and pH, but not the KH (they will disassociate to Na+ ions).

The small amount of magnesium bicarbonate will increase the KH marginally (Mg2+ ions), but it is really in there as the "anti-caking" agent, they add it to table salt "Because of its water-insoluble, hygroscopic properties MgCO3 was first added to salt in 1911 to make the salt flow more freely." It is also the ingredient of heart-burn tablets "milk of magnesia".

The contains carbonic acid bit is misleading (and belongs here) it comes from this "magnesium carbonate can also be synthesized by exposing a magnesium hydroxide slurry to carbon dioxide under pressure (3.5 to 5 atm) below 50 °C, which gives soluble magnesium bicarbonate":

The "borax" (sodium tetraborate decahydrate) is actually the pH buffer, it is a very alkaline buffer and would buffer the water up to about pH8 or higher if there was more of it. The "decahydrate" bit just means the salt contains a lot of water (Na2B4O7·10H2O), it's the 10H2O.[/i]"



> I cut with a bit of tap but as far as I know my tap is stable. However, I also dose EI in my main tank and have been wondering if this is all I need. I.e. surely there is enough calcium and magnesium etc in EI mixes for what the fauna need? Maybe even in TPN? In addition I am concerned about the build up of all of this which is exacerbated by the use of the tap water. My TDS just after a 40% water change (but including 1/5 the weekly dose of ferts) is around 170. A week later it is 350+. Maybe just going pure RO is fine?



If I lived in London I would definitely try and put as little tap water in the tank as possible, as the tap water is mainly fairly nasty. I don't see any reason why you can't just use 100% RO, if you are adding TPN or using EI etc. You could always add a small amount of potassium bi-carbonate if you were worried about the dKH being too low.

cheers Darrel


----------



## hotweldfire (28 Oct 2011)

Darrel, this is really really useful. You know that I've had some disasters in my nano and am now pretty sure that was down to very very low dKH. So want to avoid that happening again. Having just bought an RO unit being able to add something in case the ferts aren't doing it gives me a lot more peace of mind and means I can stop using tap water or adding sodium in the form of the remin solution.

One question though - is potassium carbonate as good? I note that fluid sensor online sell it but am struggling to find a pure form of bicarbonate.

The other concern which I assume I share with Pete (if not sorry for the hijack mate) is what shrimp need for healthy shell development, moulting etc. There's a ton of commercial products from Japan etc which cost outrageous sums of money and I have been guilty of parting with hard earned cash for. I suspect all I need to add is magnesium and calcium. 

Does anyone know if there is enough of that in a standard EI mix? I use 50ml of Aquarium Plant Food UK's liquid plant nutrition mix a week.


----------



## dw1305 (28 Oct 2011)

Hi all,


> One question though - is potassium carbonate as good?


Yes. 


> The other concern which I assume I share with Pete (if not sorry for the hijack mate) is what shrimp need for healthy shell development, moulting etc. There's a ton of commercial products from Japan etc which cost outrageous sums of money and I have been guilty of parting with hard earned cash for. I suspect all I need to add is magnesium and calcium.


 Yes, shrimp will need calcium for shell development, but they aren't like molluscs, the shell is a protein, chitin, calcium carbonate matrix. How efficient they are at acquiring calcium will depend upon the native water they live in, if they come from very hard calcareous water (like our native Crayfish) they will need a lot more than if they come from naturally soft water.  I would be very surprised if there is any advantage of the specialist products over adding a small piece of cuttle bone or similar. Food is almost certainly the major source of calcium and green vegetables, for example, are very high in calcium.

cheers Darrel


----------



## Radik (28 Oct 2011)

What you mean London water is nasty? I am asking as I think some of shrimps had issues recently and I mixed only 1/3 of tap with RO water to get at least some KH as I inject CO2. I do not want to put soda bicarbonate for shrimps. Thinking of 100% RO now but need to find something to buffer KH on cheap. Only issue I have is that Calcium sulphate takes long to dissolve so need to prepare more in advance.


----------



## dw1305 (29 Oct 2011)

Hi all,


> What you mean London water is nasty?


It is a bit of a sweeping statement, but because the SE of England is very heavily populated, and fairly dry, water tends to be in short supply. The major sources of water are the rivers the Thames and Lee (via the N. London reservoirs) and groundwater from aquifers. All of these sources are compromised to some degree by diffuse pollution, the rivers mainly just because they are flowing through very heavily populated areas, and the aquifers because of the intensive usage of their catchments by both humans and agriculture. 

This means that the water has to recieve a large amount of treatment before it is fit to drink, and even then it will have higher levels of chlorine/chloramine/nitrate/phosphate than water derived from a less polluted catchment.  Additionally because of the local geology, all the water will be hard and carbonate rich. <http://www.thameswater.co.uk/cps/rde/xchg/corp/hs.xsl/2915.htm>

These problems don't effect a lot of the cities away from the SE in the same way. Manchester, Leeds etc have areas of low population and high rain-fall very close to them in the Pennines where reservoirs can be sited, Birmingham and Liverpool have reservoirs in Wales at the Elan valley and L. Vyrnwy and Bristol has the Chew Valley Lakes.

cheers Darrel


----------



## Radik (29 Oct 2011)

Great explanation. I sometimes ago started to drink my RO water and it just tastes better. But I knew there is something wrong by observing shrimps. Going 100% RO now.


----------



## Skatersav (26 Nov 2011)

Very interesting stuff - thank you. I have a couple of comments and a couple of questions. I used to live in Edinburgh, used tap water and tonnes of success with all sorts of fish. Never really got into the planted stuff but for fish the water was awesome. I've had a nightmare since I moved to London. African rift lake cichlids hav always thrived in my tanks, but anything that prefers softer water has been a real chore. I use ro now. Just started actually about 6 months ago when I decided to really get into the planted aquarium stuff.

Couple of questions:

1. We are getting my wife's little bro a tank for his Christmas. 40litre bowl with a fairly basic but still I guess hitec set up. Pressurised co2 and all that jazz. I don't want him to have to use ro water because I think it's just too much hassle for the beginner. Therefore, do you think it is better to just treat tap water or could he perhaps collect rainwater for it? Central London... Pollution...

2. If not, any other ideas?

Thanks everybody.


----------



## matador1982 (26 Nov 2011)

I live close to Brighton and started my tank by using a mix approximately 70/30 ro/tap water mix. I was getting terrible issues with algae and since then now use 100% RO using Sera KH/PH plus to remineralise so far I've not seen any ill side affects livestock certainly seems to be doing better.


----------



## clonitza (26 Nov 2011)

Skatersav having a RO unit it's better than collecting rainwater which I think is way more polluted in the city than the tap water. Adding remineralizing salts in it it's as easy as adding a dechlorinator to the tap so I don't see any difference. 

Mike


----------



## Skatersav (26 Nov 2011)

Thanks. You're right, if you have easy access to ro water, but if your lfs is five miles away and you don't have a car then it becomes a real hassle. the cost of an ro unit is prohibitive given this is a gift.  Maybe he can start by dechlorinating tap water and I can get him the ro unit next year if it's not working out.  Good advice on the rain water. Thanks. Sav.


----------



## Big H (27 Nov 2011)

I take that as a "no" then hey guys?

Thanks


----------



## Tony Swinney (27 Nov 2011)

dw1305 said:
			
		

> I don't see any reason why you can't just use 100% RO, if you are adding TPN or using EI etc. You could always add a small amount of potassium bi-carbonate if you were worried about the dKH being too low.
> 
> cheers Darrel



How would you calculate the dosage of the potassium carbonate ?

Tony


----------



## dw1305 (27 Nov 2011)

Hi all,
Tony, according to "James' Planted Tank" it is: 





> 1.2g K2CO3 in 25 litres of water = 2 dKH


.
I haven't done all the workings, but that looks about right.

potassium carbonate = K2CO3
potassium = 39.1 gmol-1
carbon = 12 gmol-1
oxygen = 16 gmol-1
carbonate = 12 + (16*3) = 60 gmol-1
potassium carbonate = (39.1*2) + 60 = 138.2 gmol-1

1 dKH = 17.85 ppm CaCO3 = 7.15ppm calcium + 10.7ppm CO3

carbonate in potassium carbonate:
CO3 60 gmol-1  K2CO3 138.2  gmol-1 = 2.3 mg in 1 litre = 1ppm CO3.
2.3mg * 10.7 ppm CO3 in 1 dKH = 24.65mg to raise CO3 1dKH in 1 litre.

cheers Darrel


----------



## PeteA (28 Nov 2011)

Just re-read through the whole of the thread which is really interesting, but equally confusing too 

I guess that each person's re-mineralisation method is specific to what else they do in their tank and what their main focus is (plants, inverts, fish, etc).  So dosing full Ei (with possibly a little Potassium Carbonate in your replacement water) should be enough if you go that route, as should if you dose with some other fertiliser like TPN.  But if you don't dose any fertiliser (or a reduced amount) then you ought to re-mineralise your water using some method.

Currently thinking of getting a few more chemicals and following the "James' Planted Tank" mixes for both his TPN mix and re-mineralisation mix - seems to give a decent TDS level which is recommended for shrimp.


----------



## Skatersav (28 Nov 2011)

Seachem does a mix that looks relatively similar to James' Planted Tank mix... in principle at least: ie no sodium, low chloride.  I am going to give that a go because my wife is getting a bit freaked out about how one of our cupboards is looking more and more like a chemistry lab...

Sav


----------



## Radik (2 Dec 2011)

I just measured my RO after re mineralization and PH was around 10. Thanks to Calcium Sulphate. Now I am not sure how shrimp safe this would be during water changes I know PH shock is a myth but going from PH 6 to PH 10 in water change seems a lot to me. Any advice on substitute for Gypsum and in what amount for 25L as for Jame's recipe?

I am not using chloride only MgSo4 K2Co3 and CaSo4


----------



## dw1305 (2 Dec 2011)

Hi all,
Radik don't worry, the calcium sulphate (CaSO4.2H2O) shouldn't change the pH at all, it is the potassium carbonate (K2CO3) that does. It is because you have no H+ ions in the RO, meaning that the there is no reserve of acid and any small addition in alkaline ions will make the pH rise to a high level. Just ignore the pH, honestly it is almost meaningless in unbuffered water.

Using "James' Planted Tank":


> 1.2g K2CO3 in 25 litres of water = 2 dKH


cheers Darrel


----------



## Radik (2 Dec 2011)

Oh ok thanks Darrel, I turned only slightly Co2 and PH is going down quickly while drop checker is dark blue so yes you are right I am just bad in chemistry so glad to have you around 

I did test with CaSO4 + MgSO4 without K2CO3 and it increased PH so maybe my gypsum is crap? I am using digital PH meter with electrode not test kits.


----------



## Radik (2 Dec 2011)

Oh just realized... I am going to add CaSO4 to Tap water not RO water to see "PH change" as tap water is already buffered.


----------



## hotweldfire (6 Dec 2011)

Guys, I've been adding K2CO3 for the last few weeks to my nano and can't get the KH to read 2 or above. I'm throwing in up to 1.5g of it at a time into a 27l P@H cube that gets pure RO for water changes (max 10% a week). Testing either half an hour or 24 hours later shows at most a change of around 0.5 KH, usually no change. So,

- either James calculations are off (unlikely)
- my test kit is a nonsense (likely)
- something is eating up the K2CO3 damn fast

Are KH test kits able to detect this level of change? Are they relatively reliable?


----------



## Radik (6 Dec 2011)

Yes depends what substrate you have acids can reduce your KH usually some acids in substrate or water column. KH of 2 has little buffering capacity so it will crash but no worries. Now Darrel would explain it more technically what is happening. Also KH test kits are crap you need really good one. For me API is showing +1 or +2 higher than it really is. Nutrafin KH was sort of OK but there are more precise available.


----------



## dw1305 (7 Dec 2011)

Hi all,
I think this could be a "real" reading and that Radik is right, the fall of in the dKH it is probably to do with the lyotropic series and the exchange of cations (and anions):


> Monovalent ions (like K+) will also replace H+ ions, but they don't add any dGH. This is actually a 2 way process and those ions can be replaced by H+ ions etc and become available to the plant as the concentration of the ions change around the negatively - charged exchange sites of the clay mineral. This is the "LYOTROPIC SERIES":
> most tightly bound H+ = Al3+ > Ca2+ > Mg2+ > K+ = NH4+ > Na+ least tightly bound. Adding large amounts of one cation will replace others, regardless of their position in the lyotropic series. For example Na+ could replace Ca2+ on the mineral's exchange sites if sufficient concentration of Na+ existed in tank water.


You need to measure the conductivity before and after the addition of the potassium carbonate (K2CO3), if the K+ ions (which will contribute to conductivity) are being exchanged for H+ ions (which don't) the conductivity should rise initially and then fall as the K+ ions are exchanged for H+ ions.

cheers Darrel


----------



## hotweldfire (7 Dec 2011)

What sort of time frame for the rise and fall Darrel?


----------



## dw1305 (8 Dec 2011)

Hi all,


> What sort of time frame for the rise and fall Darrel?


 I'm not entirely sure, but a few readings over 24 hours should give an idea. All the K+ ions will be in solution, again I'm not sure about the bicarbonate ions, the amount of these will depend upon the carbonate/carbonic acid equilibrium. Assuming the cation exchange sites on the clays are still largely filled with H+ ions you should get an initial linear fall in conductivity as K+ ions replace H+ ions on the clays, and H+ ions replace K+ ions in solution. I think this decline in conductivity will slow down as the conc. gradient between the substrate and water lessens.

Cheers Darrel


----------



## David Shanahan (13 Sep 2016)

I'm a bit confused.

You go to you local fish shop, buy some RO water from them, then add your Macro and Micro nutrients. So will these buffer the water (with a little bicarbonate) or do I have to go out and buy a remineraliser from someone like JBL.


----------



## dw1305 (14 Sep 2016)

H all,





dw1305 said:


> if the K+ ions (which will contribute to conductivity) are being exchanged for H+ ions (which don't) the conductivity should rise initially and then fall as the K+ ions are exchanged for H+ ions.


This bit is actually incorrect. The H+ ions also conduct electricity. "Regani"  a chemist (who also keeps _Apistogramma) _<"explains why on this thread">.





Planty said:


> You go to you local fish shop, buy some RO water from them, then add your Macro and Micro nutrients. So will these buffer the water (with a little bicarbonate)


Yes.





Planty said:


> or do I have to go out and buy a remineraliser from someone like JBL.


No.

If you have hard tap water you can fulfil any calcium requirement by just cutting the RO with a small amount of tap water.

If you want a more scientific approach have a look on <"James' Planted Tank: Re-mineralising RO"> it gives recipes for raising both dGH and dKH.

cheers Darrel

.


----------



## Staticrzr (21 Oct 2016)

hey guys.. I'm in the same boat here. 
I'm thinking of buying a RO unit as most of the journals which I follow and love here are using RO water. The other reason I'd that my water here is very very hard. 

I know for a fact that Viktor from GreenAqua  is using salty shrimp to remineralise his water. - he uses either his own EI recipe or ADA ferts. 
I also know that Luis Cardaso is just using plain RO water with his own recipe of EI which just contains more than MgSO4.7H2O. 

Given the fact that I never used RO water I'm in a crossroad.. which patch to choose? Maybe I'll get some input from some of you guys who are actually using RO.


----------



## sciencefiction (21 Oct 2016)

hotweldfire said:


> Darrel, this is really really useful. You know that I've had some disasters in my nano and am now pretty sure that was down to very very low dKH.



Definitely the disastrous case. Out of all "measures" the KH is the most important bit. It also gets used up in various processes, including nitrification so it needs replacing to keep the water stable. How much of it gets used up depends on the particular tank set up.



Radik said:


> just measured my RO after re mineralization and PH was around 10. Thanks to Calcium Sulphate. Now I am not sure how shrimp safe this would be during water changes I know PH shock is a myth but going from PH 6 to PH 10 in water change seems a lot to me. Any advice on substitute for Gypsum and in what amount for 25L as for Jame's recipe?



Don't dwell on your Ph. When re-mineralizing water, get one of those TDS electronic test kits and mix the water to the same reading each time, providing you are using the same source of mixers, whether tap water or other dry stuff.  The individual readings of Gh, Ph, etc will vary. You just need 1-2 dKH to hold the water stable and the same TDS reading after the water is mixed. If you try matching individual readings, it gets messy and mostly bad for the fish.


----------



## Staticrzr (22 Oct 2016)

Staticrzr said:


> hey guys.. I'm in the same boat here.
> I'm thinking of buying a RO unit as most of the journals which I follow and love here are using RO water. The other reason I'd that my water here is very very hard.
> 
> I know for a fact that Viktor from GreenAqua  is using salty shrimp to remineralise his water. - he uses either his own EI recipe or ADA ferts.
> ...



ok, I've done some more reading and this is what I have. 
use RO water,  add your EI solution based on the amount of water you have, check tds using a tds meter. If TDS showing lower than 120-> add salty shrimp and aim for tds 120-130.  
You don't have to worry about pH if ur using soil similar with Ada Amazonia which keeps it pH stable at around 6.7-6.8. 

Is this about right?


----------

