Black algae on sand?

[Kingumar]

I am having a bit of an algae problem. With some brown algae on sand and rocks, I also see a lot of black colored alage. What is that? What causes it? I just did a wc and will be doing them more often, as well as run carbon.

Heres a pic

 

http://img11.imageshack.us/img11/5633/2012042423485219.jpg

Edited April 25, 2012 by Kingumar

[treesprite]

Cyano bacteria?

[Pants]

How old is the tank?

[BigWyll]

I 2nd the Cyano bacteria. I have some in the dead spots in my 120g tank where sunlight shines on through a nearby window. I also had an outbreak in my 2nd tank that nearly cover half my 50g. Easiest remedy that I found was to turn off your lights for 3 days. Cyano all gone.

[SunWyrm]

It's cyano, I get all kinds of colors of it in my mantis tank and only red in my reef tanks. I had my lights off for over a week with my mantis tank (which worked, he just has a ton of nutrients and not much flow, gotta fix that) and when it came back it was crazy colors.