Has Any One Tried This?

[MTbeachgirl]

Wondering if using an opaque 8ml drop cloth would work to help heat the water. Anyone ever tried this?

[PaulR]

Usually a "solar cover" is essentially bubble wrap. The main benefit is you don't lose as much water through evaporation, which helps the water not cool off as much. I've heard that the darker covers also reduce your chlorine consumption because you don't lose as much to sunlight. Some people also claim the bubbles focus sunlight to heat the water better, but that's hogwash.

--paulr

[chem geek]

The bubbles do contain still air that is insulating, so there is less conduction of heat in addition to the reduction in evaporation. I notice this difference in my own pool since my pool cover is opaque and thin. It cuts down overnight temperature drops to around 3ºF (depending on how cold the night is), but others in my same area and pool size using a bubble cover have about half as much temperature drop overnight. With no cover at all, I see a 6ºF temperature drop. So bubble-type covers are indeed better at retaining heat. I agree with you that they don't really "focus" light and in fact you don't want anything interfering with the sunlight except to block UV. Letting infrared and visible light into the pool will heat it. I write more about the absorption/heating of light in pool water here.