So the spa guy came and he replaced the seal (two pieces really). They both look just fine. I don't see any wear on them, corrosion, cracks, blisters, fraying, anything! Of I'm not home when he fixes it (and he didn't leave a note or a bill for me). I thought for sure if it was a water chemistry issue that I'd see *something.* Well, maybe they were loose, or just went bad. Time to fill the tub back up and see if she leaks anymore.