When should I run my solar heater???

[BBBliever]

This is my first year with an AGP and as fall is approaching I will be installing a 4x20 fafco solar panel to my 2000 gallon AGP tomorrow.

Current day time highs reach the low 90's upper 80'S in my area of California. With a solar cover my pool is around 85 deg. by the end of the day. I know the temps will be falling fast soon and want to make the season last as long as possible for my 3 y/o daughter.

What temperature ranges should I look for to run my solar panels. Lets say the minimum temperature I want to maintain is 70 deg. At what ambient air temperature would I run the solar panel. I have heard automatic solar controllers kick the panels on when the ambient air is 10 deg. higher the water temp. Is that the guideline I should follow?

Maybe this will be covered in the Fafco instructions but I was looking for some experience from the board. Thanks for your time.

 

[linen]

I typically run mine when the sun is out and it is on the panels (I have shade from about noon and after ~8 pm in summer), even if the ambient temp is lower than the pool water. Also, I have found that when it is cloudy, as long as the ambient temp is equal(close to) or higher than the pool temp, I get a net heating effect due to some solar coming through the clouds.

Some of this stuff I figured out by measuring my pool temp and measuring my return temp under different conditions.

Also, when the sun is on the pool and the pool temp is close to ambient, I take my cover off and get more direct heating from the sun (I have one of the cheap blue tinted covers which filters some of the direct solar). A clear cover would be best, since "heat of evaporation" effectively reduces the water temp slightly (and requires refilling at some point with usually colder water), which is one of the reasons water, if kept at a stable ambient temperature will always be slightly cooler than the ambient temperature.

Temps here are dropping fast (ambient air temp was 32F this morning)

 

[BBBliever]

Thank you linen, that is exactly the info I was looking for.

Hopefully my daughter and I will be swimming through October with the help of fafco.