Hi! My pool company winterized my pool last September, came back to open April 15. The water level was low…about a foot of water in the shallow end…is a 25,000 gallon pool. We refilled while waiting for them to come out and finish opening, and the water level has remained very stable. Any thoughts as to how this could have happened? The pool cover has rain vents, we don’t use this area frequently in the winter but did not notice pooling water. Liner is about 7 years old, we have a light and deep end ladder. Thanks!