agree with all you said, mas. first thing i was thinking when i read the pool size and idea of 1.5 inch lines is "go 2 inch lines'. i have about a 14-15,000 gallon pool so less than half the size (that's going to be a big ass pool!) with 1.5 inch and 3/4 hp (soon to be 1 hp) pump and 6 hours twice a day for turnover seems reasonable.i can't see turning over a pool your size with 1.5 inch lines without running the pump well more than half a day for a turnover!