Raising kh with a buffering soil?

[PuddlesAquaFarm]

I am trying to convert one of my CRS tanks to be able to house royal tigers. I have ADA Amazonia in the tank as substrate. Parameters have been pH 6.5, kh 0, gh5, tds 150. I want to raise kh to 2-3 as I've read that is best for tigers. I added baking soda and brought the kh up to 4, a little high but I was happy, and pH rose to 7.0. Next day kh was back to 0 and pH back to 0.

Now I know this is a buffering substrate and was expecting a pH bounce back, but was not expecting kh to return to 0. I assume the substrate absorbs the kh. I'm willing to change substrates. But I am wondering how anyone maintains a kh of 2-3 when using a buffering substrate? Don't they all do this? My potential source uses Azoo plant substrate which buffers but he has kh of 3.

Any advice would be great!

[timster14]

do you have a planted tank to house your CRS? as plants take up the carbon?

i think with the baking soda trick is to add a little bit each day to get the ideal KH, but i havent tried with baking soda before, and i know something like crushed coral works

some salts will also raise the KH.

[PuddlesAquaFarm]

I think I am going to use crushed lava rock as an inert substrate. I'll rely in the kh level to maintain a stable ph and will avoid driftwood so as to avoid tannins. I found aomeone who does this and has been successful so that is what I plan on doing. This will be in a separate tank and I will continue keeping CRS for now.

[octanejunkie]

I have CBS in a 2G cube bedded with EC (eco complete) and a single seriyu stone in the tank. Plants include ambula, some ludwigia, HM and some floaters like amacharis and dwarf water lettuce. There is a single piece of cholla wood that i boiled the tannins out of that the shrimp like to munch on. The pH is stable but a bit high at 7.2, haven't tested KH or GH in a while. I remineralize RO with SS GH+ The shrimp seem happy and there are shrimplets in there doing well.

[hyoushoku]

If you are using the baking soda, you need to make sure it is Potassium Bicarbonate and not Sodium Bicarbonate. Or else, too much sodium will not be good for shrimp health.

You need to add the bicarbonate for about 2 weeks to a month to completely exhaust the ADA AS, then the kH and pH will go up.

Another trick to maintain pH and kH is to add Calcium Carbonate. It is slower to dissolve and can maintain the pH between 7.3 to 7.8 very well. The best way to tackle your problem, use Potassium Bicarbonate during water change and add Calcium carbonate daily.

By the way, Royal Tiger still can survive in acidic water pretty well. What they need are plenty of calcium and trace supplement. Calcium supplement can be from calcium carbonate powder, crushed oyster shell powder (I don't favour this option as it contain mercury) or limestone powder.