My dad wants discus, clown loaches & perhaps a few tetras in his 45 gal tank. He knows how big CLs get but he lives on the second floor and plans to use the tank as a grow out tank, buying a 120 gal for the basement in the future. The problem is the water out of his faucet is very soft and acidic. I tested his aged water and I get the following pH 6.2, KH 40 ppm, GH 25, Nitate 20 and everything else is like 0. Is there a good way to buffer his water? Add coral maybe to his aged water barrel and tank filter? And what water parameters work well for CLs and discus together? I know a bit of aquarium salt work well with CLs but how about discus? Any help is appreciated.