It sounds like staghorn algae to me, I had it for a while. I'd take that with a grain of salt though, I'm far from the most experienced person here. I had it while going through my new tank syndrome, before my nutrients balanced out. Very tough to remove, nothing in my tank would eat it. Once things balanced out, it dissapeared.
90 gallon, flourite, HP Co2, jobes sticks, Leaf Zone. 440 watts VHO lighting, home built canopy.