Last year I had a small leak in my sand filter where the top screws into the fiberglass housing. I replaced the gasket and used silicon grease but I still had a small leak. I just went out to my pool equipment and now I have a large leak. I'm thinking that the fiberglass on the vessel where the gasket sits is porous and that may be my problem. Is it possible to smooth out the fiberglass using a resin, JB Weld or some other sealer that would provide a less porous surface for the gasket to sit on? Other ideas?