Ideally, your pump should run a few times a day, but this isn't a necessary requirement at all. Rather, having it run a sufficient amount of time to keep the pool skimmed, and clear to your satisfaction level. Most importantly to keep FC distributed throughout the pool, particularly in dead, or poorly circulated sub surface regions as opposed to stratified layers. Stratification in reality isn't a cause for concern if a pool is used or circulated daily at all. You will not burn off enough Chlorine in any layer to allow Algae growth, because it simply doesn't work this way.