Too much of a good thing?

Good news... bad news. Tank was set up on 12-3-16. Went through a serious stage of hair algae. It was everywhere and long! Now it is all gone and the coraline algae has been growing like crazy on everything, including the glass. It doesn't come off the glass with the magnet cleaner, and there are already scratches on the glass from the previous owner (bought the tank used).

I don't want the coraline algae to start distorting the view into the tank, even though it is a pretty color. What is the best way to keep it off the glass? Razor blade it off?