Join Date: Oct 2006
Location: Leesburg Virginia
PH swings caused by CO2 (carbonic Acid) have little affect on fish. When I do a 50% water change, my ph goes from 7.4 to 6.4 approx. and I have never had fish show distress from it. I have had the same Cardinals for over a year and usually it doesn't take much to kill them. The ph swings that stress fish are swings related to bicarbonates and other minerals. More specifically, TDS (total dissolved solids) is what fish are often sensitive to.