I am trying to set up pH control with the Profilux 4 using CO2. I am only interested in lowering the pH. The current setup has a solenoid that activates when the pH gets too high. The logic is set up as a cycle but this method overshoots and too much CO2 is added, dropping the CO2 too low.

I can possibly add a regulator to the CO2 to lower the amount coming in, however, this is added cost. Could this be changed in the logic to have the solenoid open for 3 seconds and then stay closed for 30 seconds to a minute before it opens again?