Wanted: Mustard algae or suspected mustard algae

[chem geek]

There was also a recent report in this post on another forum where using PolyQuat 60 appears to keep away yellow/mustard algae as well, though it's a bit too early to know for sure. So use of an alagecide, either 30-50 ppm Borates (by the way, what is your Borate level?) or weekly PolyQuat 60 combined with chlorine keeps away yellow/mustard algae without needing the higher chlorine levels.

We know from other users that keeping the Free Chlorine (FC) level at a minimum of 15% of the CYA level will keep away yellow/mustard algae without any need for an additional algaecide, but it appears to be a rather hard limit and a high FC level that some people don't want to deal with (it's about double the "minimum" FC of 7.5% of the CYA level for green algae that roughly corresponding to Ben's "Min" column). Others have shocked their pools (and equipment -- poles, etc.) at FC levels of 60% of the CYA level and eliminated the algae, but it wasn't easy. So there are various options for people.

Richard