So I decided just to use CPVC. But I have a question about draining the panels. I dont think ill ever completely drain the panels as the pool is above the pump equipment and the solar. Im wondering if I need to a solar valve with a drain back hole in it, or if I can get by with just using a normal 3-way valve so I can use it to also isolate the panels, rather then needing to plumb a 2-way isolation valve upstream of the 3-way drain back valve.
