We are having a new 33' installed in a few weeks and are looking at underlayments. The pool store didn't recommend anything and they typically just use sand. After researching on our own, we think we should do more and planned to purchase a gorilla pad. I've run across the generic 'elephant pad' and wondered if anyone had any experience with these? Are they truly comparable? Would love to save some money where we can, but don't want to regret it.