Sorry to hijack your thread, but I also have a leaky seam issue on my Intex 18x52 metal ultra frame. It is brand-new, just out of the box for 2 days. It had less than 2 inches of water in it when we noticed the tarp had small puddles forming in several spots around the pool. I don't know if it's one or several leaks. The ground is miraculously level and free of any debris, so I know that's not the issue. I figure since it's brand new with potentially several leaks, the whole seam may be defective and an overlap liner would save a lot of the headache that's bound to come with trying to patch inside the little flap on the bottom seam.
Before I take the new overlap liner leap, I was wondering if there was possibly some vinyl sealant product that I could paint or smear or caulk inside around the bottom and center seam to seal that little flap down ? Wet application or dry; there's only an inch of water in it so it wouldn't take much to dry it. I don't know if they make a product that will bond to the vinyl and stand up to the chemicals, but I imagine it would be cheaper and easier to try that first.
Any thoughts are appreciated !