[nycman]

My PH is the only parameter that I have not been able to adequately control. It drifts between 7.8 and 8.1 or slightly lower. I tried many things, at same time and independently. The big three were 1) airing out the fish room with fresh air (I live in a new house that is tightly sealed), 2) dosing kalkswasser in my ATO, and 3) using a CO2 scrubber with CO2 adsorption media attached to the air inlet on my skimmer. Have to say, after a few weeks of isolating variables it is 3) CO2 scrubbing that did the trick. My PH is no stable in the 8.2 to 8.35 range.