I'm a volunteer pool operations person for 72K gallon neighborhood gunite pool.
We have a Polaris C-660 controller for the main and for a 2.3K gallon wading pool.
The ORP control drives two 24vac solenoid valves to control flow into the (Hayward) chlorinators into which we put regular Trichlor 3" tabs.
The solenoid valves get clogged with debris, stop working, etc. Whats the point in having a sophisticated controller when the weak link seems to be these valves. They are expensive ($230 from Polaris?) and a pain.
I've seen the Intermatic valve actuators - which for almost the same price, would seem a better control solution.