I have a 15 x 30 / 3' x 7' and I'm running a hayward maxflow II 1 1/5 HP pump 240V.
Its a SP2810X15: Pump Output (GPM) vs. Total Resistance To Flow (Feet of Head) ==
20ft/83, 30ft/74, 40ft/64, 50ft/51, 60ft/34
I have 1 1/2 inch pipe with two pool returns...