What is this algae?

[bat21]

Tank has been running about 10 months. Just started noticing a few little patches of this stuff. It's brown and slimy and is like a film but turns stringy as it moves back and forth in the current. Phosphates are zero, nitrates < 5. Have literally never measured nitrates above 5.

It's a 65gal fowlr, and the picture is of a small piece of fake coral. What is this stuff?

 

[cloak]

Cyanobacteria would be my guess. This doesn't always have to be that purple/maroon color were all so used to.

http://www.reefcleaners.org/nuisance-algae-id-guide

 

[Bogue Chitto]

I think cloak is right.

 

[bat21]

Thanks guys.