I had a crack in the bottom of my skimmer a year ago (2012) I used JD Water weld two part putty, you knead to mix and soften so you can fill, cover area to seal. It has worked fine for my problem, Now what I'm looking for is a sealant, or glue to cover 9.5 in. base of skimmer so crack ever grows it will be waterproof and can't leak again. Do I use silicone or epoxy , I would even use some 45 mil. liner to seal it, I just need to know the best sealant to use underwater ? Thank You