bad algae or coralline?

[pyro]

I have some stuff on the glass (sorry no pictures at the moment) that I thought was algae... I ran my mag float over it a lot and took off all the glass algae, but was left with green spots here and there, especially around the top 2" or so of the tank. It feels almost like coralline when I try to get it off, but looks like pesky algae.
Just wanted to get anybody's opinion on it, thanks.

 

[granny]

I get the same thing in my tank. NOt sure if it is coraline or just algae 'scum' that calcifies in the salt water. Anyway, it takes a razor blade to remove it. You can purchase a longhandled tool with a stainless steel blade for just this purpose.