I can vouch that it works on hair algae. Surprisingly, doesn't work on Marimo balls. Yeah, I accidentally left the ball in the tank when I put the Algaefix in (the 2nd time I dosed didn't hurt it either). Also the tank had mosses and those weren't hurt.
My Marimos have lasted through multiple H2O2, Excel and Algaefix treatments. It suffices to say, if it ever becomes a pest...I'm in trouble.