Need advice

[Apryl]

I am not new to aquariums but this is a new problem for me. I decided to set up at tank after a few years without one. Did not have this problem last time a tank was up. 55 Gal. Cycled with the filter media of an established tank. Tap water is 7.0 PH; doesn't change when aeriated or after sitting. The problem is KH is 5 and GH is 0. After 4 days water is depleted of KH and PH begins to drop rapidly. How do I raise KH and GH levels without raising PH to high. Live bearers and barbs in tank.

 

[V227]

I believe your listed fish could easily handle a ph of 8-8.5. To keep the ph steady include a limestone rock, like Texas Holey Rock in your aquascape, or add some crushed coral in your filter media basket.