4 to 6 hours depending on season, but not all at once.
I run the Polaris for 30 minutes after the waterfall does a 30 minute cycle, which is twice a day mid AM and early evening. That is to pick up any trash the waterfall has created. Then for 3 hrs in the afternoon for the main cleaning cycle. I run the pool filter in the coolest hours of the night, midnight to 8 AM to keep the pool cooler.
In the morning it is actually chilly, but after the waterfall and polaris run there are hot spots. One where the spa spills over as the main filter runs when the polaris runs, the other near the waterfall. Very weird swimming down the pool in the afternoon; warmish in the shallow end, then cooler, then warm, then cooler still, then very warm, then very cool in the deep end.
In the winter I reverse, and the pool runs in the heat of the day and the waterfall too. The polaris runs during the day then as well, for more like 6 hrs total since there are so many leaves then.