Yellow mustard

[PoolDoc]

Yellow Out is an ammonia salt, probably ammonium chloride. I think they used ammonium sulfate at some point over the product history, but I don't believe that's the case now.

If you follow the instructions on the bottle, AND raise the pH to 7.8+, you'll end up with 2 - 3 ppm of monochloramine in the pool. Monochloramine is the least irritating of the 'simple' chloramines or combined chlorines that the swimming pool industry talks about. It is VERY effective against mustard algae.

BUT . . . being LESS irritating than dichloramine or nitrogen trichloride, is NOT the same is not being irritating. 2 - 3 ppm is somewhat irritating to all swimmers, and extremely irritating (severe itchy skin rash) to some. As a result, you'll have to close the pool while it is in use. Then you'll have to shock repeatedly to remove the monochloramine. Also, if you have an ORP system, you'll have to disable it while the Yellow Out is in use.

Using it as a precautionary measure is not even something that I think the maker would recommend. It's effective in removing mustard algae IF you follow directions PLUS raise the pH. But if you use it, you need to be ready to pay the piper, with respect to the severe side effects.

Good luck.