I don't have a lot of it and it doesn't seem to be proliferating. Sorry for the title error. Can't figure out how to edit that.
Hard to tell from the picture here out the water as there are a few different species of bryposis we encounter.
It appears to be bryopsis sp. which is the general name given in Julian sprungs algae guide.
It's rather soft compared to other tough corse forms and had a larger developed central hold fast once grown out.
Usually found in newly set up aquariums growing on the glass, overflows and then on the sand.
If it is this type then don't freak out as it's not typically the plague of death bryopsis most have major issues with.
While I was fallow during a tank transfer with all new live sand I started to notice this brown in color short algae growing on the overflows and back glass.
Turned out it grew rather quickly into green bryopsis sp.
I let it grow till the central hold point was developed enough I could use my finger nail to easily detach it from the surface.
Set my water mixing trash can next to the tank, used a small clamp to hold a filter sock around the rim of the can and utilized a scrapper and siphon hose zip tied together.
Just run the end of the siphon hose into the filter sock.
When the can gets full just pump the water back to tank and change filter sock if needed.
Now I did this three times during a 90 day fallow period
Once my tangs were out of QT they made short work of this delectable green snack along with my blennies.
So if you have this type as I did then algae loving fish will mow it down.
I let it grow out two weeks before adding my algae starved water cattle back to the tank and within 3 hours there was not a trace of green left in the tank.
On another note this type is said to go away on its own as it's viewed as part of the new tank "uglies"
My advise is be proactive in manually removing it best you can and get some algae eaters like tangs, urchins, blennies or sea slugs
Good luck and happy reefing
BluewaterLa / mike