Quote Originally Posted by fuelman View Post
I am having a hell of a time this year with Mustard algae.
I think I'm gonna add Borax to 50ppm asper the posts I have searched.
Will this kill off the algae or must I kill it before I add the Borax?
How much Borax and how much acid will I need to reach 50ppm?
I come up with 34 LBS. Borax & 2 GALS., 17oz. of acid.
Could I try Seaklear Algae Prevention & Remover
This is chelated copper sulfate. I would not recommend it, although copper is the ONLY algaecide that actually kills algae besides chlorine and bromine. All the others just inhibit it.
or SeaKlear Yellow Klear
This is sodium bromide. It would be my first choice but be very careful NOT to overdose. It will take repeated shocking before your FC holds since it temporarily converts the pool into a bromine pool. This is an effective product if your CYA is high and not as effective if it is in normal range. If you have mustard algae then I suspect that you either have higher than average CYA or you are not maintaining your FC.

and if so, Which? I'm kinda leaning towards the Algae Prevention & Remover.
Thanks for any help!
If you would post a full set of test results I could make a better recommendation. Often plain chlorine is all that is needed but with a vinyl pool you will have to bring the levels up fairly high and might suffer some bleaching of the liner.
The borates, to the best of my knowledge, won't really kill the mustard but are very effective at inhibiting it once it is under control. However, I don't know for sure so it could be a worthwhile experiment. I seem to recall some people on this forum saying last year that borates were the only thing that kept the mustard from returning but I don't know if that is what they used to kill the outbreak.

Are you SURE that you have mustard and not pollen? They are often confused and I noticed that you have in your sig that your water is cold. Mustard is much more common later in the swim season when the temps are much warmer.