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Remineralisation salts for RO water

a.d.wood

Member
5 Year Member
Hi folks,

Any one have experience of making DIY remineralisation salts??

I've been using RO water filtered through peat in the past which seems fine for the apisto's in the fish house, but I have a couple of projects/ideas where raising the GH/KH a little bit might be an advantage.

Anyway long and the short of it is I bypassed the RO membrane this weekend after a test on the tap water revealed it now had a GH of <1, (was GH 3 when we moved here 4 years back, jumped to 9 a year or two back, hence the RO unit)

Tap water now just goes through the pre filter, carbon and coconut block to remove any 'nasties' (and the tap water GH now checked every time before filling the water butts just to make sure it is still <1!!), so using treated tap water or similar to raise the GH ain't going to work!!

I've used Kent RO right in the past, but it's expensive when you consider the litres of water involved (and rumour has it the sole UK importer of Kent Marine has decided to drop the range). I've had a look around and found the following recipe:

Per 10 gallons of water > 1 tablespoon marine salt, 1/2 tablespoon sodium bicarbonate. They reckon this should give a GH of ~2 and KH of ~4

Any other recipes????

Thanks

Andrew
 

tjudy

Moderator
Staff member
5 Year Member
Please consider that marine salts add significant amonts of KH to the water. I use RO Right because the amount of KH it adds is less than marine salts. When I was reading the DATZ book on the Apistogramma (the book with teh A-numbers), one of the things that stood out to me was teh statement that breeders in Germany have stated that the GH is nto nearly as important as the GH and pH when setting the water parameters for spawning. That is a real boon, because it is relatively easy to set a KH and pH using chemicals if you are not going to be concerned with a GH that jumps up three or four points higher than 'optimum'.

What I do is use three different products that each adjust one of the different parameters. I start with RO Right and increase the GH to 1/3 of my goal. This adds a little KH. If I need a higher KH, the second product I use will adjust the KH. Sodium bicarbonate will work, but it has a tendancy to become unstable over time, especially in the presence of acidity... so there is debate about using it as a pH buffer. The last thing I adjust is the pH. Usually I am driving it down with Kent Marine's pH Control Minus. Once I have done that I retest everything and find that the GH is up close to where I wanted it to be, because adding the KH compound and the pH compound increases the GH.

So whatever chemicals you decide to use, try the three step approach... testing betwen each addition of a chemical... and see where it gets you. If you record everything you add to get the perfect mix, then you will have the recipe you are looking for.
 

ed seeley

Moderator
Staff member
5 Year Member
RO Right

Hi Andrew,
Powdered RO Right as you say is no longer available here, certainly I can't get it!

I looked at making my own replacement from MgSO4 and CaSo4. In RO Right and Seachem Equilibrium these chemicals are in the ratio of 3 CaSO4 : 1 MgSO4. Seachem Equilibrium also contains some other elelments (See their website, http://www.seachem.com/products/product_pages/Equilbrium.html, for more details).

In a thread on another forum I discussed this and worked out the chemical ratios needed to replicate Equilibrium and found that it was not economical to to buy them seperate, unless you have a cheaper source than I do! Here's the thread, http://www.aquaessentials.co.uk/forum/viewtopic.php?t=613, and here's the maths I did to work the concentrations out;

Powdered compound Grams needed
K2SO4 43.5
CaSO4 34.7
MgSO4 24.7
FeSO4 0.30
MnSO4 0.16
Total weight 103.3

This should give a percentage concentration that will do the job.

After all the working out I costed it up and I now have a 600g tub of Equilibrium!
 

a.d.wood

Member
5 Year Member
Hi Ed,

I'm in the process of organising a shipment of artemia cysts from the USA and have asked about sourcing RO Right and shipping it with the order.

I'll have a look at the ingredient list above and get some prices from our chemical suppliers, maybe.....

Andrew
 

five

New Member
5 Year Member
Hi Ed, so nowadays you use your own salt mix to remineralise your RO water? Or do you use the Seachem Equilibrium?

Currently I use direct DI water filter through peat. I did not add anything to remineralise the water. Is there any cuase for concern?

Hi Andrew,
Powdered RO Right as you say is no longer available here, certainly I can't get it!

I looked at making my own replacement from MgSO4 and CaSo4. In RO Right and Seachem Equilibrium these chemicals are in the ratio of 3 CaSO4 : 1 MgSO4. Seachem Equilibrium also contains some other elelments (See their website, http://www.seachem.com/products/product_pages/Equilbrium.html, for more details).

In a thread on another forum I discussed this and worked out the chemical ratios needed to replicate Equilibrium and found that it was not economical to to buy them seperate, unless you have a cheaper source than I do! Here's the thread, http://www.aquaessentials.co.uk/forum/viewtopic.php?t=613, and here's the maths I did to work the concentrations out;

Powdered compound Grams needed
K2SO4 43.5
CaSO4 34.7
MgSO4 24.7
FeSO4 0.30
MnSO4 0.16
Total weight 103.3

This should give a percentage concentration that will do the job.

After all the working out I costed it up and I now have a 600g tub of Equilibrium!
 

ed seeley

Moderator
Staff member
5 Year Member
Five,
I worked all this out (from the molecular weights of the different chemicals) and then worked out that Equilibrium was cheaper so went with that!

Almost everyone says that you have to add something back and you can't keep fish in pure RO/DI water. I'm not so sure. I only add tiny amounts of the remineralisation salts into my water as I want very soft water. What would be the difference if the GH was 0 rather than 1 or 2? There may be some issues with skeletal growth I suppose, but do they get the minerals they need from their food? If it's working for you and you haven't seen any problems then I suppose it's ok!

Andrew,
Let me know, both about the RO right powder and the chemicals. I reckon you add a trace mixture for the FeSO4 and other minor constituents so all you would need to do is have the following four in these proportions:

K2SO4 260 grams
CaSO4 210 grams
MgSO4 150 grams
Trace Mixture 3 grams

To buy these seperately would have cost me more than the Equilibrium, but this was a retail price, from another source it may be very different!


I was interested in what Ted said about RO Right raising KH a little. I found that however much I added the KH stayed at 0. All RO Right did was raise the GH. I've not thoroughly tested the effects of Equilibrium yet as I've only just started using it.
I run all my tanks with 0dKH and have never seen any problems from alleged pH crashes. But then, as the pH drops a degree in my main tank when the CO2 switches on every day and the fish do not mind at all, I'm not sure pH is something that actually effects the fish as much as most think.
 

Graham

New Member
5 Year Member
I think pH crashes are only a concern when there is a long period between water changes/heavy stocking and the KH is minimal. I also use peat-treated RO with a very minute amount of CaCl, MgSO4 and K2SO4. I try to keep the makeup water 50 ppm or less.

Back in the day when I was "doing time" working at a LFS, we tried to change the Betta water with straight RO/DI. Every one of them died within 45 minutes, so I think there's something there. If you think about the concentration of solutes in the fish vs. in "empty" water...that's got to be a factor.

Even addidng pure RO during a water change (assuming it's not a 100% water change) will leave some dissolved material in the tank water (from waste, decay, etc). The likelihood of it ever being zero is minimal. Though I agree that I don't know how much difference a few ppm makes, I think it must be a factor.

Another thing I consider is the needs of the plants in the tank. If I want them to keep using nitrate, I need to make sure they have everything else they need as well. That includes Ca and Mg.
 
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