> You say your pH took a jump from 7 to 7.6. Did you take that first reading > right after a water change? Sometimes a tank can become more acidic > immediately after a water change. I believe this is because of the > dissolved CO2 in solution. The tank will become more basic as the CO2 > escapes. For dwarves that I soften the water for I let it sit out overnight > before I alter pH and do water changes. I put tapwater as is into the A. > cacatuoides tank and they don't seem to mind. Hi, The water pH change describes an increase in pH and therefore alkalinity after the water change (if there was one). This is usual for me too as I use tap water which is made intentionally more alkaline by the water companies. This is in compliance with UK guidlelines as acidic tapwater is more likely to dissolve metals (copper and in old properties lead) from the pipes. After a few days it reduces from pH 8.5 (out of the tap) down to 6.5-7 in the tank. Hope this helps, Ken.