What type of Algae is this?

[bjorn]

I can't figure out what type of Algae is this?

It only seems to grow on Stones and Wood, very short 5-15mm at most, very strong green colour, and grows in tufts or round spots. Can't remove it easily either. Does not grow on the glass. Grows in high flow areas.

Any ideas and why I have this?

 

[mdhardy01]

Looks like bba to me I know it's green but I think it comes in a range from green to near black
Matt

 

[bjorn]

Thanks, I was wondering if it wasn't BBA, but all the images and references I saw mentioned it as "Black". Otherwise it does match the description.