Have a 25k gal gunite I'm having redone in two weeks with PebbleTec. Worried I may have overlooked something..... Pool gets drained slightly/winterized/covered every September and opened in April due to the large number of trees I have. The amount of leaves we get in the fall makes this a necessity. I know their warranty is fairly strict on maintaining chemistry year round. Are there serious issues with keeping a pebbletec pool covered for the winter season?