I understand that this substrate lowers PH,KH/GH. I have very hard water and I was thinking about buying some of this soil, but I have one question. How do you change the water without causing harm to the fish? I would imagine that a wild KH/GH swing once a week can't be good for the fish. I use tap water without any RO/DI water.

I think others will agree, im sure that the swing cannot be that drastic, most of the folks here with soft water dose gh booster and fish are fine. So going from harder to softer should be ok. Also looking around i did not see any posts where ada lowered hardness, where did you find that info?

Ok thanks, I guess the drop in hardness is not that great.

Here is the link where I read about aquasoil dropping the kh in the water

Aqua Soil Substrate

I think most of us see KH as being alkaliniity (ppm of carbonates) and GH being hardness. Apparently Aquasoil does lower the alkalinity, but I don't know how much.

Thanks VaughnH.