Question On Chem Geek's Best Guess Chart

[Jack Sparrow]

The chart shows a column for Yellow Mustard.
1. Does this mean that if you've had yellow mustard in the past that these are the numbers to use?

2. If this is the case, there's only a minimum number-- is there a "target" number?

3. Can I revert back to standard numbers if I'm using an algaecide?

Thx-
Joe

[chem geek]

Jack,

The target column is really just a guideline for maintaining a pool free of green algae. It's really the minimum column that is most relevant since always maintaining chlorine at least at that minimum is what is required. So I didn't bother to create a target for yellow/mustard algae and you would just have to maintain more than the minimum to ensure that you never get below the minimum.

As for when one needs to use the yellow/mustard minimum, that depends on whether or not this algae gets reintroduced into your pool frequently or not. If you completely get rid of it through high-level shocking and you thoroughly clean ALL equipment, swimsuits, etc. that can go back into your pool, then you can try going back to the normal FC levels that prevent green algae. But if the mustard/yellow algae gets reintroduced, you'll have to fight it again. Keeping the higher minimum will prevent mustard/yellow algae growth even if it gets reintroduced.

And yes, if you use an initial dose and than a regular weekly maintenance dose of PolyQuat 60 algaecide, this should prevent algae growth in general for both green and yellow/mustard algae. We know that green algae won't grow with PolyQuat 60 present even if there is no chlorine, at least for quite a while, but we don't have direct experience on how effective the algaecide is against yellow/mustard algae. Buckman Labs told me that it is effective at inhibiting yellow/mustard algae growth, but didn't give me specific numbers for how effective. My guess, and it's just a guess, is that using PolyQuat 60 plus some level of chlorine will keep away the yellow/mustard algae and the minimum chlorine level for green algae combined with the algaecide should be more than enough.

Richard