You need to run the pump enough to completely turn over your water volume in a day's time. One of the equipment guys around here may be able to tell you, based on your pump, how long that is--but I would think that 8-10 hours a day would be plenty. I have approximately 26K gallons in my pool, and 8 hours is enough time to run the pump, although I just make it easy and turn it on when I get up, and off at dusk.

Janet