How to raise the KH of RO-water.?

Question

Hello :)


Just wondering what's the best way of raising the KH of reverse osmosis water?

I have been using some "sera mineral salt" for hardening the water, and using "sera kh/pH-plus" for raising the KH, but I find that I can't get the KH high enough as the pH gets too high.

The pH of my RO water is perfect so I just want to raise the KH so it stays that way, this stuff raises the pH too.

I read about using like baking soda, which is a nice cheap option, but when I went to the cooking drawer in the kitchen, we had:

"Baking Powder" and "Bicarbonate of Soda"

I am guessing I will be using the latter, but just want to make sure.

Just so you know - the baking soda contains:
• Wheat flour
• Raising agents: Disodium diphosphate, Sodium hydrogen carbonate

The bicarbonate of soda only has bicarbonate of soda in it.

Also, how much would I add to raise the kH by...say 1dKH?

Thanks

Thanks for all the great replies! :D

Firstly, as for raising my GH - I don't need to, and as I mentioned I am using "sera mineral salts" to do this.

As for raising my KH, I have solved my problem.
Using "sera KH/pH-plus" I used to only raise the KH a little before the pH was getting to high. This was my problem.

I have solved it by simply shaking the bottle before hand xD

I feel a little silly that I didn't shake it before, but now I get a KH of about 6/7 and a pH of 7.5 which is pretty much perfect for me.

Thanks for the interesting responses re. the bicarbonate of soda, and if I am in a sticky situation I know I can always resort to that if need be.

Thanks again,
Panda

Thanks for all the great replies! :D

Firstly, as for raising my GH - I don't need to, and as I mentioned I am using "sera mineral salts" to do this.

As for raising my KH, I have solved my problem.
Using "sera KH/pH-plus" I used to only raise the KH a little before the pH was getting to high. This was my problem.

I have solved it by simply shaking the bottle before hand xD

I feel a little silly that I didn't shake it before, but now I get a KH of about 6/7 and a pH of 7.5 which is pretty much perfect for me.

Thanks for the interesting responses re. the bicarbonate of soda, and if I am in a sticky situation I know I can always resort to that if need be.

Thanks again,
Panda

Answer 1

The baking soda (bicarbonate of soda) will work, but it will also change the pH. The major mineral it provides is sodium, but the carbonate hardness will increase.

If you need to raise general hardness (measures the concentration of calcium and magnesium) as well, I use a marine product called OsmoPrep (by Kent Marine) - this is made to replenish calcium, magnesium, potassium, and other minerals removed by the RO process. It may be a little more expensive ($6.95 when I bought it), but this might be a better product to use long term. This will also raise the pH somewhat.

As far as the amount to use, that would be hard to predict without knowing anything about the pH and alkalinity of the water you have. Adding small amounts at a time and testing in a few hours would be the best way to determine the amount needed in the tank, then just add the amount needed to the replacement water when changes are done.

Answer 2

The baking soda will also increase your pH some. Sera does make a KH additive but I have never used it. I've always had good results from using formulas made for RO/DI water. Aquarium pharmaceuticals has a few out there. I use their Electro-right and pH adjuster and get pretty balanced results. I haven't had a brackish tank in a long time and didn't use RO water in it so have no experience there. Experiment with varius differant products to find the ones that give you the results you are looking for. Try reducing the amount of salt you add before you add your pH/KH adjuster. You just need to find the balance of the GH, KH, and pH

Answer 3

Use the sodiumk bicarb, better still put some rocks in the tank to do it naturally. It's all pot luck really, whenever I change the chemistry, I use a teaspoon, add it to the water then test it after a few hours. If it's not raised enough repeat the process again until you get the desired result.