Black Algae? How worried should I be?

[Jeff Shaw]

Hey guys, wondering if this black algae is something I should be concerned with? Just noticed it this week.

FYI, I am doing weekly water changes (10%) but what else can I do to stop this?

 

[cloak]

Looks like Cyanobacteria IMO. Assuming parameters are within reason, manual removal along with increased circulation throughout the tank has been known to help. GL.

 

[Jeff Shaw]

Just tested water, only thing that's abnormal is Nitrates at 5ppm, will do an extra water change and will see about increasing circulation. Thanks for the response.