I tend to just add CO2 1/2 prior to the lights coming on, that adds plenty of gas during the photo peroid without the risk.

But yes, you can run a pH controller/solenoid adding CO2 at a higher rate for the day cycle also.

So adding CO2 to maintain a stable pH is really not the best of methods really I think. It works and all, but you get better results adding more and less fish stress at night when the lion's share of the 24 hours is low CO2 and relatively high O2.

Most folks run their light for 10-12 hours, so 12-14 are no CO2.


Regards,
Tom Barr