Mustard algae or something else?

[mm3846]

Hey all, I've been trying to fight these stains for a while now. Finally went to SLAM+ for mustard algae. Have all my tools and robot sitting in the pool getting disinfected.

The thing is, it won't go away and brushing doesn't do anything. Is it possible its something else? Metal stains?

Pic has a little other debris in it, but the stain is clearly large and visible. Its on 3 sides of the deep end. Pool is otherwise crystal clear.

 

[mknauss]

If it is organic, setting a trichlor puck on it for a few minutes will remove it. If that does not effect it, then it is a metal based stain.

Any copper containing products used in the maintenance of the pool?

 

[mm3846]

If it is organic, setting a trichlor puck on it for a few minutes will remove it. If that does not effect it, then it is a metal based stain.

Any copper containing products used in the maintenance of the pool?

I'll try that trick when I get home.

Nope, no metal. Just liquid bleach.