Maybe more of a "handyman" question but I'm hoping someone here can help me. A couple of years ago, a big mouse or rat (ugh) chewed the threads on the filter drain valve. He/she chewed a V shape up (widest part of V at bottom) to slightly into the filter itself. I had enough threads to screw on a metal valve (which even Godzilla rat can't chew) and that doesn't leak. My problem is that there's a tiny chewed area that the new valve can't cover - the part in the filter itself and it's extremely difficult to get to. I try to seal that every year with some kind of waterproof sealant and it still leaks a little. I don't remember what I used last, some kind of two part that you mix from HD. It seems to dry out and pull away from the filter. Does anyone have any suggestions as to what I could try that would "stick" to the filter better? Thank you.