Thanks to both of you, but I"m pretty sure it's not either of those
Myka, your pics look more like that plating algae that was bothering that one acro.
I'll try to take some more pics to see if anyone else has ideas. It's taking over...probably 20-25% coverage of my rocks now. It comes out when I pic at it in big clumps as if you chopped off a piece of sponge material. It's spongey actually.
One possibility might be Fauchea sp?
http://reefkeeping.com/issues/2007-0...s/image025.jpg