I swear I should patent this. But someone should make a matt that is black and would sink to the bottom of your pool. Like a solar cover, but that sinks and is black to absorb the sunlight. Then once the pool is as warm as you want it you take it out. It amazes me all the people that have really light blue or almost white colored pools and then wonder why they never warm up. A friend of ours is building a new pool, she originally wanted black pebble Tec but the dealer told her the pool would get to warm. We are in Wisconsin for crying out loud! For the 2 weeks it is really hot you could run a fountain, but for the other 12 weeks you need all the heat you can catch.

Maybe I am crazy and it wouldn't help.