My pool was closed this morning. The pool professionals lowered the water right below the returns, which is about 20" from the top of the deck, and 6" below the bottom of the skimmer. I don't think that we have a high water table but it kind of makes me nervous that they lowered it this far--especially since it started raining right after they left and it is supposed to rain 1-2 inches this afternoon and evening. Is it customary to lower a fiberglass pool this low when closing with a mesh cover? Could my pool suffer any damage from being lowered this far right before it rained?