"Jeff & Kathy Brown" wrote in message
...
If my KH is 90mg/L and GH is 40mg/L, why am I having pH swings of 7.6 in
the morning to 8.8 in the evening? Thanks.
Kathy


Seems strange, but I believe KH of 120 to 140 is preferred, so a little more
buffering could not hurt. Secondly, assuming you are actually using up all
that buffer, some carbonates disolve (recover) faster than others. So
perhaps a faster reacting carbonate would help.