I borated a pool with Boric Acid a few months back, and now that the weather has warmed up, the tile-line several inches up has turned white. I've tried a mild acid/tile cleaner wash with minimal results.

Any idea on why this happened?

Thanks.

- Jeff

An acid soap mixture almost always works. Perhaps you didn't use a strong enough acid. Try using one part 31% muriatic acid to ten parts of water and see if that does anything.

I can't think of any reason this would have anything to do with borates. There is nearly aways some white scale depositing at the water line regardless of borates or not. You can minimize this by keeping the CSI slightly negative, but you can't eliminate it completely.

whats weird is in my notes there was a pretty clean tile-line in April. I added Borates in May, and within a week or so it got warm.

Then, the tile "hazed" all of the way up to the coping, not just at the tile line. pH has been between 7.6-7.8, t/a at 80-100. I sprayed about a 1/8 mix of 31% with some tile soap added and it hardly made a dent.