[untamed]

Originally Posted by martym

My RX has only one chamber
here is how Randy Homles set his up. This is from is article on Reef Central.
"A more elaborate method is to connect the solenoid valve to a pH controller and place the pH probe into the calcium reactor. The valve then switches the CO2 on and off to maintain a target pH within the reactor. I use a similar method. The pH probe is placed in the tank, and switches off the CO2 flow to the calcium reactor only when the pH in the tank has dropped too low (e.g. pH 7.8 or lower).

This is how I run it, but I try not to let the PH get that low.

I get it. Randy is using low-pH as an emergency shut off for the reactor (at tank ph 7.8). By setting your shut off as high as 8.0, you probably shut down the reactor for most of time that your lights are off.