Hi Guys, if You are talking about the white stringy stuff, I have a ton in my tank. It started out growing out from under a well established Zoa covered rock I got a couple years back. I always thought maybe it was the way it spread like their roofs as its completely covered that rock, and now braching out more, but the Zoas arent expanding with them. Now I am concerned. Its a 30G tank that all my corral has outgrown, and about the step up to a 100G tank, and a completely new setup, and already apprehensive about the changes, and unknown. I will see if I can get some pics. The white stuff I have is pretty brittle, and will crunch off it handled, but is in too many nooks and crannies to even try to remove without destroying ALOT of corral now. Thanks D