This is my 3rd summer with the pool (2 winters). Could my filter gasket have already gone bad? It's leaking a lot from behind the band clamp. I took the gasket out, cleaned it, re-lubed it, re-set it. I always give it little whacks as I tighten it. It is my understanding that helps to set it properly. I can't see anything physically wrong with it. It's not dried up, or brittle at all. I have a replacement gasket on the way tomorrow, but since the current one looks fine to me, I'm doubtful that it will solve my problem. What else could it be?