Black algae or metal stain

[PoolDoc]

To affect black algae, you have to (a) have high chlorine levels AND (b) brush the heck out of it.

[Crazziee]

Okay, I will up my brushing

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someone needs to invent a power brush with a spinning head, Would make my life easier...

[Watermom]

Look at the bright side ---- you will build up your muscles brushing!

[PoolDoc]

Keep in mind, we haven't established that any of those spots ARE black algae. The most definitive test is to scrape some off with your fingernail, and smear it on a white card: black algae will smear dark green.

Brushing will make plaster wear through spots WORSE!

But, if you DO have black algae, a brush like this

Pentair R111616 604A Algae Brush with SS Bristles, 6-Inch

will help.



NOTE TO OTHER READERS: Do *NOT* use a metal bristle brush on fiberglass or vinyl pools, EVER!