I have a leak around the main seal of my Hayward DE filter. I've check the gasket for damage and the lip of the filter looks fine. I've taken the black band off and on several times and reseated the cover and made it as tight as I could but after 30 minutes it starts leaking again. Any ideas? Since I opened the pool this year I can't seem to raise the PH (TF100 reads pale yellow) no matter how much Borax I add. Could this have led to the problem (damage due to acidic water?)? Thanks in advance for reading my post.