There's a calculation somewhere in one of the threads so that you can determine how many hours it would take your pump to move the entire volume of your pool water through it. You want to run your pump at least twice that time. For me that was 8 hours total so I run the pump 4 hours in the late morning into early afternoon then late afternoon into early evening. That way if I add chemicals at the end of the day, they get circulated. Do whatever works best for you.