I have read many posts on the subject of Mustard Algae. Most asking, “Do I have it?”

But find no definitive description to identify it, and I have been unable to find any clear picture of it online.

I did find the following descriptions:

- 1. Appears as yellow powder deposits usually on the shady sides of the walls.

- 2. A yellow film, usually found on steps or walls.

- 3. It is a yellowish-green color and does brush off the walls easily

- 4. A wall clinging variety usually found on the shady side of the pool. It is sheet forming.

- 5. Most often is seen as patches of dark yellow dust that covers various parts of the pool walls and floors. It usually starts in corners of the pool, near the steps, by the ladder, and other areas where the water circulation is not good. Unless the algae gets into cracks, pits or crevices of the pool surface, mustard algae will brush off easily.

What I wish to know is if anyone has positively dealt with this and can give a clear definition from that experience? Also does anyone have a picture?

I often find yellowish dust on the bottom of the pool, never on the steps or wall. Thought this might be Mustard Algae but now thinking it is only fine dirt. Looking to clarify this as I suspect others also make the same misdiagnosis.
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