Which valves are the best to use. I want to be able to control the water flow thru the valves. The pentair valves have stops that allow you to divert water @ different flow rates. Does the jandy valve allow you to do this (ie. keeping the valve @ half open without the valve slipping back full open). Also the jandy are CPVC and the pentair can be bought CPVC or PVC. Is it an advantage either way? I will have valves on all returns, skimmers, md, & waterfall.