I believe its red macro algae. If you have tangs, they will eat it with a quickness. Put it anywhere that will get good light. You can put it in the refugium too.
I can't grow it. I've tried a couple of times in my fuge, but the chaeto choked it out. I can't put it in the DT because the tangs would eat it in seconds. Maybe someone that can grow it will see this and chime in...