Am I doing something wrong? I am in the north east where we get some periods of snow and freezing weather. I have always lowered the water level just below the skimmer and placed a rubber plug inside the return jet. As the cover get rain and snow on top it displaces the water in the pool out thru the skimmer which I leave open. By next season the pool level is about a foot lower than the bottom of the skimmer. Is this what everyone else is experiencing? I do leave the cover loose so it does not pull on the walls as it gets heavy. What about a skimmer block off? How does everyone here address this issue? I also have a valve out the bottom of the skimmer which is left open, have heard water in the skimmer will crack it as water freezes.