What is the best way to run the pump for the pool? The pump flows at 60 gpm, so the water turns over in about 4 hours. My plan was to run the pump for 5 hours a night from, say, 9 PM to 2 AM. But my dad was very insistent that the pump needs to run twice a day, once in the morning and once at night (he says 3 hours a piece). That seems weird to me, since it would never get a full exchange either time. Which is better?