I'd like to remove any unnecessary check valves (or use 2-1/2" inlets instead of 2" inlets) so as to improve my circulation flow rate. (I've already removed a few unnecessary 90's and the pool heater with dramatic results!)
However, I've heard that check valves can cause a significant head loss on any system (I have the Jandy no-lube type). Is this true? Where can I find a place which lists typical PVC fitting (and valve) head loss calculations so that I know where I can optimize my circuit best?