AGP installed last July. Opened up middle of May and cannot get the pump to stay full of water. I checked everything. Removed all unions connections etc. changed all o-rings even though the o-rings were good, lubed everything etc. Changed the pool pump lid o-ring as well. Did the water test, smoke test and I cannot find where an air leak is if there is one . The pump is a Hayward Variable speed 2.7hp. All 2 in piping. All lines were blew out at the end of the season last year. Any other things I can do? Really frustrating.