Does anybody know what these little gray balls are?

[surferd31]

So I saw a little round ball floating around in my overflow and thought nothing of it, but then I was moving around some frags and saw 2 more of these dark gray, almost black balls on the a plug. Anybody know what these are?

http://i43.*******.com/2yo94t1.jpg

[surferd31]

nvm i figured it out

[Anemonebuff]

I bet they are actually greenish. Looks like Valonia/bubble algae.

[Anemonebuff]

Pull them out by hand and try not to pop them. They reproduce when popped. They feed on nutrients in the water.

[robs.mark]

+1 bubble algae fo sho!