I have yet to experience pH being "too high" due to scrubbing and the need to turn it off or control it with a controller b/c often times its quite the opposite where even with scrubber it doesn't get it high enough b/c it has to work against the other surface exchange (overflow, DT wavemaker, etc) that's actively exchanging more CO2 (assuming the cause of high CO2 is high ambient room air) back into your tank. But, i guess each tank is different so if your situation is lucky enough where the scrubber is "too effective", you can do what @yman182 suggested above to set up an automatic control.
I haven't. Its mainly morning and night that it dips. Once It gets to around 3-8pm it gets closer to 8.2. Sitting at 7.9 atm.
yup, tried that - i think mine has to do with the "good" air exchange inside the skimmer and it just can't keep up with the rest of the "bad" air exchange in the rest of my system. i'm content with where its now, swing between 8.1 - 8.2 just jealous of the people that can consistently maintain it at 8.3. =P
are you dosing Alk daily? if so r you already using sodium carbonate? i found that if you just need to boost it slightly (.1 - .2) range, this is an effective alternative, esp if you spread the doses to multiple smaller doses every few hours at night when it's low. This is what i do to keep it at mostly a .1 swing between day/night. offcycle fuge also helps.
