I have a pool that has been above 80 degrees fahrenheit during the night. Recently I went for a swim just after sunset and noticed that I could see what appeared to be steam or some kind of vapor moving over or coming out of my pool. Now I thought it can't be steam, because steam is water in the form of vapor, which would have be to at 212 degrees fahrenheit! The air temperature is probably in the 60s at night, and I have a chlorine salt generating pool. Does anyone know what I am seeing and can anyone explain this to me? The only guess I have is that it has something to do with convection currents...but I don't know. I can't see how something can be evaporating out of the pool, because it's pretty cool at night; unless something is evaporating all the time, but I can only see it against dark backgrounds at night.