Dude, u talking to tha master (just kidding! I can only tell u what I went through...
) here!
Best way I found to get rid of local Bryopsis after killing many of my corals, is using 100% peroxide to fight the beast!
If u treating Zoas, take them out (Rock) if u can, piss them off so they all close up and take 100% .03 Peroxide with a pipete and squirt it around the colony/frag as much as u can for about 30 secs, 60 if u brave! I would try 30 first though...
Then, rinse it in tank water. Repeat if u need to, but that's the best way I have found to work. Dipping in 50%, 30% even 20% mixed H2O2/H2O either kills the coral or doesn't do jack-squat IME.
As Danny said, H2O2 and SPS is pretty much 100% SPS death rate.
If dealing with SPS, get it out of the tank, scrape as much of the Bryopsis as possible and then use the 100% peroxide around the base of the frag really carefully. It has always worked for me (after I learned my lesson
).
FYI, u should think about reducing Phosphate and Nutrients in ur tank to fight it long term and help go away. GFO and Bio-Pellect Reactor is what did it for me.
Good luck my friend, I feel ur pain....
Higor