I'm wanting to know how much hot water it would take to change temp in 27000 gals by 3 degrees. We have an instant water heater we've considered using temporarily. Thing is, our pool is in shade most of the time (only in full sun about 4-5 hrs a day) so it doesn't get much opportunity to get real warm. It's been unseasonably cool here this summer as well so looking to explore our options without spending a fortune. Currently, the pool temp stays around 76-78 but has been up to 82 for a few days so would like to get it back at least there or better & keep it there for the rest of the season. Considering a solar cover to get help hold it there once attained. All opinions welcome.