yep..between the lack of water evaporation and the shade from the sun, really does help a bunch. i would suggest when it's calm..say after a nice day of swimming in the early evening if it's calmer and sun is down but it's still fairly warm outside, leave the cover off for 2 or 3 hours a day instead of one. leaving it on for toooo long will make it like a greenhouse and promote algae growth..last year when i first got my cover and it was july and high 20s to low 30s, i left my cover on for 3 days and that's all it took for an algae bloom. chlorine was gobbled up at a much faster rate and it went from 5 to 0 in a couple of days and i figure by the morning of hot day 3, i had zero chlorine and one day of no chlorine and the heat was enough to make a mess..now, i'll add that was when i didn't have an swcg for steady output of chlorine and i can't remember if i was using cya to stabilize the chlorine or not at the time.