When it is extremely hot, like this summer (day after day of mid 90s), I add bleach and turn the pump on in the evening and let it run until the water sparkles. Sometimes it hits that point by bedtime and sometimes it needs to run all night. When the pool temp hovers around 86-90 degrees, running it at night keeps it from climbing any higher and allows the chlorine to do it's job without me driving my CYA level higher and using more bleach.

When it is just warm (days in the low to mid 80s) I run the pump in the early morning or afternoon and turn it off before bedtime. I have less heat loss this way. I have teenagers at home that can turn the pump on and off when I request (theoretically- if they can tear themselves away from vegging away in the house). I'm just too lazy to use the solar cover anymore, because it precludes the sudden, impulsive dip in the pool whenever someone is in the mood.