I want to squeeze a couple more weeks of pool use out of the Fall, with below-average temps. Unfortunately, I was not advised to install a retractable cover when they built the pool 20 years ago, and the cost to rip up the coping, install guides and a well, and put in the cover is ridiculous.
However, to keep the pool warm enough to do my PT (88-90 degrees) in it every day for an hour, I could easily burn through 400 gallons of propane a week!
I tried a solar cover, but the thing required four men to put on and off - the pool is 18x54, and if water gets on top of the cover, forget it. I returned it. So, I just bought a couple of 20x30 4 mil waterproof silver and black tarps, and laid the across the pool. I have no idea if that's going to provide any insulation and prevent heat loss at night. Any opinions??
I guess I could just leave the heat off one night and see what temp the pool drops to, but I have noticed that it's a bad idea to let the gunite cool down once it's up to temperature in the summer -- it's better to keep the pool warm, and if it drops to 75 overnight, I'm gonna have to heat the concrete back up to 88 along with the water!
Does anyone think a 4 mil plastic tarp like that will be helpful? It seems to me it has to reduce evaporation. I don't see any steam coming off of it in the morning!