So I have this large residential system, we're just about to finish things out. 3" mainline thats about 700ft long with about 15ft elevation change from end to beginning. We have a 3HP Sta-rite DHG pumping water. Its turned on via pump relay. I'm guessing the internal check valve on the pump is allowing some leakage down because it takes a long time to fill up the mainline (being 3" and X cuft of water) and so forth. Periodically theres a 2" threaded tee that supplies 2x Hunter 2" PGV valves and the irrigation zone Should I put in a pressure switch (with small tank) instead and keep the mainline pressurized, or let it be non-pressurized while the system isnt running. What's your thoughts, professionals?