How to Spot (and Fix) Black Algae Early

Black algae is actually a cyanobacteria, and it's notoriously difficult to kill because of its protective outer shell. It loves the porous surfaces of Florida pool tiles.

Identification

It looks like small black or dark green spots. If you try to brush it off and it doesn't move, it's likely black algae.

The Treatment

You must physically break the shell of the algae with a wire brush before applying high-dose chlorine treatments directly to the spots. It often takes multiple rounds of "scrub-and-shock" to fully eradicate.