I do close my pool for the winter, but do not cover my pool either. The water stays clear all winter long. I do have a little dust on the bottom when we are ready to open it up, but that is easily vacuumed up. Pool covers are a big hassle!

Our fellow moderator, Al, aka Poconos, lives in northeast PA where it gets really cold and snowy and he also doesn't cover his pool in the winter.