Well I am new and I don't know at all. But I looked on the hitch hiker thread and it looks like this:
Bryopsis Algae
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Bryopsis Algae is a type of hair algae that can be very problematic in our home systems. There are very few animals that will eat it and it can grow aggressively. The Fox Face LO and Lettuce Nudibranch are the only two animals I know of that has been known to eat Bryopsis. I got a Fox Face which did an excellent job and keeping it maintained. From what I read it seems to be more dominate in new tank and older tanks, likely due to the nutrients in the system but IME it can become a problem even in low nutrient systems.
You can go here and check it out for yourself https://www.saltwaterfish.com/vb/showthread.php?t=163868
I get a little of that in my overflow, I pinched a piece off and my tang ate it. He didn't seem to like it as much as the normal fuzzy hair algae though.
IMO, tangs dont eat that alge,maybe a little but i dont think so.I just peeled it off it comes off in big clumps, watch out for britsle worms underneath..