Not having much success looking on-line for a simple floating (not attached to anything) blanket to cover our 15 X 30 in-ground pool. Aim is more to mitigate evaporation, than retain heat. We've a heat pump to warm up pool water during the day. Would like to just purchase whatever material is needed, and then cut it to fit pool. We live in south Florida, so pool is used all year 'round. All suggestions most welcome. Thanks very much.