ID please? This stuff is tough

[maxima k2]

I have had this algea in my tank for a few years now and nothing that I have found is even interested in it. It grows in tightly packed bunches and is almost impossible to rip off the rock in. I once tried and the rock it was on broke before the algae let go. I have been thinking of using wire cutters to trim it back but want to ID it so afterwards I can control it.

 

[saltyseaman]

That sounds and looks like Briopsis to me. Do a search for briopsis and you will find a lot of info. When I had it nothing seemed to do much to it either. I kept it under control by ripping it off by hand ( a very tough task indeed). Then one day my Yellow Tang decided to take a bite and 2 weeks later it was gone, at least out of my display tank. It still grows in my fuge. HTH and good luck