Dark purply threadlike algae

[Cromileptes14]

I have in my 29 gal reef a dark algae. I can't put pictures up right now, but if anyone knows about this help would be appreciated. It is a drak, purplish-black algae, and is stringy. It grows very fast, almost doubling its area in one day. ANy ideas on what it is and how to control it are wlelcome.

 

[melosu58]

I say it`s probably cyano. Read this

http://www.aquariumadvice.com/articles/articles/20/1/Cyanobacteria-AKA-Red-Slime-Algae-/Page1.html