I do plan to ask at the local pool supply tomorrow, but their employees aren't very helpful, so I thought I would try you smart people. Our pool has the normal row of tiles around the top BUT the tiles don't completely butt up against the top. Instead there is about 1" of white plaster or thinset or grout (but doesn't look like the grout between the tiles). Whatever it is is really dirty and even seems to be wearing away. After watching some pool tile repair videos I really think it's thinset and the geniuses just used it to cover the space when they laid the tile. I'm wondering if I could just put another coat of 'something' on top that would cover it up and look better? Maybe a water proof caulk? This area is above the waterline unless we get major rain and the pool overflows.

Any ideas? We tried cleaning it last year and maybe it helped a little, but where it's wearing away I need another solution. We had the pool replastered last year, but they wouldn't touch the tile or above. We didn't think to ask for an opinion.

You really can't even see this area (the pool edge hides most of it) unless you're IN the pool, so I don't need a gorgeous solution - just serviceable!