I have a new inground pool this season (installed in November and promptly closed) and wanted a second opinion on a slow prime... The pump is roughly 4 feet above the surface of the pool, so I understand the physics to this... but initially after install the pump would run 30 minutes before priming. I thought this was excessive and the pool company came out and installed a check-flow valve near the pump, but only on the main-drain line. So... when you shut the pump off, you lose water down the skimmer pipe. I tried moving the inlet valve to shut off the skimmer just before shutting off the pump and I still lose all the water out of the basket and it takes nearly 20 minutes now to prime. Any thoughts? Have the pool company install a check valve on the skimmer line also?