In times of extreme heat, like this week, you want to pay more than usual attention to your chlorine levels. The higher the temperature, the faster your chlorine levels evaporate. Run the pool pump during the day, if not twenty four hours a day, so there is constant circulation of your water , thus constant circulation of chlorine in the water. Have some bags of shock on hand, and test the pool each night when all swimmers are out, and shock the water if the chlorine level is low. This will ensure that as the next hot day breaks, your pool water will have enough sanitizer in it to ward off plant life(algae) and will help it keep up with the more than average amount of swimmers. Happy Swimming!