Split off of this topic. JasonLion
If you want the best flow with the least amount of TDH go with larger plumbing 3-4 inch, the TDH of a multiport valve, typically seen on sand filters if 50 ft head, and sand filters do not work well on low flow, the debris does not penetrate the media bed as far as it should and pressure will rise faster. A cartridge is a very good way to go, will also eliminate a backwash valve which can be a large amount of TDH. On your plumbing make sure to use 90 degree sweeps and not elbows, a 2" elbow on TDH is almost 9 ft head, so 90 degree sweeps or 45 degree elbows if you have to. You can find charts that will provide you with the amount of TDH for the plumbing that you plan yo use and then you can add it all up on the suction and pressure side to get to a number, then look the pump curve of the pump you plan on buying, then purchase accoringly. You ought to look at a vs motor or a 2 speed motor, you will like the electricity savings.