Will auto cover keep pool water cooler in full sun?

[Ahshort]

I have a green auto cover on my pool. Pool is in full sun, temps in the 100’s during the day. I uncover and run pump at night to keep water cooler, which is my main goal here. During the day would it better to keep cover on or off? On it shades the water but there is prolly heat transference from the sun hitting the cover as it lays atop the pool water. With cover off I’ll get evaporative cooling but solar heat gain. Then I was thinking, maybe cover on but spray it down every couple hours to keep cover cooler by evap so would lessen heat transfer. Any thoughts?

 

[rcs29]

Well since nobody else chimed in. I have a navy blue cover and I live in a drastically different climate but I'll share my experiences. I actually am trying to do the opposite of you and keep my pool water warmer. I keep it covered when not using or planning to use. By keeping the cover on my water temp remains higher than if it is left off. The exception to that is if it is getting direct sunlight then I'd say the difference is slight but I believe the sun heats it up faster. The cover seems to retain the heat more than increase it. By the sounds of your issues it may be beneficial to look into a chiller? I know this probably doesn't help much but that's my experience in NE IN.

 

[wgipe]

My experience is the same as RCS. The fastest way to lose heat is evaporative cooling, and the cover prevents that, so I would expect that keeping the cover closed would only serve to raise the water temp faster.

 

[an1vrsy]

I/we have an auto-cover and a chiller. Weird summer this year here in Las Vegas as we are not having the 100+ temp days in a row like we did last year. This year it is like 95 every day and we have a lot more cloud cover without the rain. In my opinio, if the clouds are here give us some rain. We are in an historic drought.

Summer 2021 we ran the chiller every day from the end of June till Labor day. We were able to keep the water temp out of the 90s with the chiller to about 85 - 86. We closed the cover at night to reduce evaporation and would open the cover and crank up the chiller the next morning. If we left the cover open overnight we’d probably drop another 3 degrees to 82 but we’d also lose water to evaporation. Again thinking about the drought.

This summer we are only using the chiller a couple days a week if the water temp creeps up to 90 degrees. So, cover open during the day, water temp gets up to about 88, cover closed at night, water is like 84 - 85 the next morning. Cycle repeats.

 

[gingrbredman]

I have a dark grey cover, and find if I leave the cover on, in the direct sunlight, my temps will rise during the day. In the early months of the season, this works well for us to get a little more heat into the pool without running the heater, and the same in the month before we close. I have looked at this many times, so can be sure with the cover on, and a dark grey cover, the cover acts like a solar cover and does increase the water temps and does not lower it with the direct sun. In the hottest part of the season, we do leave the cover open overnight to let the water cool down a bit if we are getting in the upper 80's, 90's water temps.