Do solar covers really help bring up or retain the water temp?

We have been using a solar cover as protection against raccoons that would otherwise get in the pool at night. It is extremely effective at warming up the water but later on in the summer the water gets too hot, I'm thinking of trying a leaf net over an air pillow to help raise it above the water when temperatures start getting really hot. Just hoping it will work to keep the raccoons out.

IMO, solar covers do slow down the movement of water (the top layer), by some amount (which is hard to determine), and this is what retains most of the heat while the pump is running. If the day is warm and wind is very low, then the cover should be removed or at least peeled back (50% of more on the pool) to allow the pool to breathe and the pump to run. I take mine off half way if no one will be using the pool during the day to allow the pool to breathe and work more efficiently. A lot also depends on wind speed. I have small flotation devices and if they blow off the pool, then the cover stays on.

Best thing to do is use your judgement and experiment to figure out what works best for your pool. You must put the cover at a night (right after the pool is closed for the evening) and remove it by around 11 a.m. My cycle is from 1 p.m. - 6 p.m. for the pump (6 hour run time). Only reason for this amount of time is because the heat pump takes long to maintain the heat.

I notice the skimmer not working as well with the cover on catching what ever is floating on surface. much less evaporation and cuts daily chlorine addition sometimes by as much as 50%. We have no shade at all over pool. Normal Circulation of water is not effected, pressure gauge stays at 12-13 mostly and FC levels always adjusts with chlorine addition correctly.

rajung said:

Normal Circulation of water is not effected, pressure gauge stays at 12-13 mostly and FC levels always adjusts with chlorine addition correctly.

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Yes, chlorine consumption will decrease and the pressure will not change because the plumbing is full of water and no air is present in the system. I am always wondering if the hottest part of the surface, right underneath the cover (check the water temperature on a hot day) and you will be amazed what the difference is between surface water (first 2") and the heater inside the plumbing the pump is transferred fast enough through the system and the heater.

The heat pump manufacturer (with my system) claims that temperature going in to going out is a 4* difference. If the water is 80* to start with and the surface water is 90*, then the water coming out would be 94*, making heating up the water pretty fast. Without the cover, the wind can cool down the surface pretty quickly (think about eating hot soup) and blowing on the spoon (within seconds the soup cools down).

From what I can gather, solar covers retain 3*-4* overnight from evaporation loss (depending on the State you live in), and really there is no need to purchase greater mil expensive covers. A 10 mil cover is sufficient, and even an 8 mil may work. Also, cutting a cover in half will have no ill effect because your whole goal is to retain the heat. To add heat, a heater is a must.

Clear solar covers will in fact protect from evaporation and also add some heat as the suns rays can actually penetrate it. But they look horribly dirty 99.99% of the time ???

I buy the most inexpensive solar cover every year. They only seem to last one season where I live in Cali. I'm okay with $30 a year extra expense some may not be. Anyway, they do help retain the heat that the pool has accumulated during the day. You should not leave the solar pool cover on during the hottest parts of the day. Like others have said it is best to remove it or peel it back 50%. I have found by doing this your pool will actually heat up faster and stay that way longer. My regiment is at 8pm put solar cover on. At 7am peel it back 50%. If we are going to be swimming that day I just take it off. My AGP gets sun from 6:45am till 7pm during the summer lol. If I do not follow this regiment and leave the cover off. I will lose roughly 1in of water to evaporation during the summer. It gets hot here. That's a lot of water after a couple days to replace. Replacing water everyday or every few days jacks up your salt, ph, stabilizer...just about everything so you end up creating a ton of extra maintenance for yourself.