I'm going to add some solar panels as soon as my pool is completed. I'm even having the builder put in the 3 way manual valve but can have the handle replaced and adapted to an actuator. I figure I'll try to operate it manually this first winter and see what happens and what kind of pain it is.
Anyway, I know the panels have a recommended flow for optimal efficiency. Using the 3 way valve, I can divert a portion of the flow to the panels. But how do you know what is optimal? How can I measure flow just through the panel without an expensive flow meter? And if I hook up a solar controller to move the actuator, can those be adjusted so they are partially open and mix the flow, or are they limited to 90 degree rotations of the valve only?