Help! Clumpy algae on sand bed ??

[bandos507]

Hi,

Recently I've been having a green clumpy algae form on my sand bed? I don't have algae growing anywhere else. Any ideas?

I stir the sand and the next day it's pretty much back. Looks like a green carpet over the sand . Thanks in advance!!

 

[Nihilus]

It might be the start of Cyanobacteria. This comes in a wide variety of colors sometimes.

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