I have a 22k gal IG. i drained the pool to below the level of the returns, blew out the lines and capped. I covered the pool, but with rain & snow the level has risen to the skimmers (I have gizmos in the skimmers) I used a cover pump last year, can't find it now. Question: If I don't drain the pool back to below the skimmers, can freezing water do damage?