Green spots on glass and rocks?

[Dewey]

I have a few green spots popping up on my glass and rocks in my 30 gallon . What is it? And how do i get rid of it? Its hard to get it off. I have to use a razor blade to get it off glass.

Thanks Dewey

 

[Civicman86]

i have the same prob, i just uped my hermit and snail count to see if they can hold it off.

 

[JG]

If it is hard to get off - probably coralline algae. I leave mine on the back glass and rocks, but will use a razor blade to scrape it of of the front and sides.

Coralline on glass has a pattern to it - circular...