I've seen posts that say you should close as usual even when planning to replace a liner in the upcoming Spring. Due to living in the dry climate of Colorado, the water level is going to drop at least half way down over winter due to the evaporation we experience. If I put a regular cover on, it will pull the sides in and down as it lowers. The draining cover (that I love) can't be more than 10" above the water level or it will do the same thing (I added water all winter last year). What happens if you just leave it without a cover?