Heather, are you putting the bubbles down and flat side up? Birds like to drink from the topside of a cover and beaks and claws can pop the bubbles - but it being the entire cover, I'd imagine that either the water chemistry or storage of the cover, when no in use, is the cause. (John, I've seen quite a few solar covers deteriorate from being folded or rolled, but it's not the entire cover and it takes a couple of months as opposed to a week or 2 , and it's deterioration from the outside (sunny side) in)