MA slam for weeks, Mustard Algae will not die


Bronze Supporter
Oct 4, 2015
Austin, TX
I have tried everything. Regular SLAM then MA SLAM. For weeks now. Wore out the steel brush. Pump on 24/7. Tried applying bleach directly on to the algae areas with a 10’ plumbing pipe (a trick a pool guy showed me once). Nothing works.

Passing OCLT but the mustard is still there. Walls and floor both so it’s not pollen. Pool water is clear and sparkly.

It’s not a case of reinfection from an alcove or light housing. The same spots in the same places never go away.

Currently FC 16, CC 0-0.5, CYA 20-30, TA 60, PH 7.2, CH250, Borate around 15. I have taken the FC up as high as 40 for several days at one point trying to zap this stuff.

I’m at a loss. My Wife wants to use copper algaecide but I’m saying, no, I believe the gospel of the TFP and BBB. What am I missing?


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Sounds like a tough one.

Any chance of a picture or two?

Copper algaecide will do nothing.

Let's see if some of our more experienced folks can give some advice.
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