cyrus I think the only thing I came across tht's supposed to eat it is the lettuce nudibranch . Most other animals can't eat it in large amounts because of some kind of toxic substance in it.
The lettuce nudibranch eats only bryopsis and will starve once it's gone. The Kent Tech-M has done the trick for me before (see above link). Once the bryopsis is gone hair algae tends to take its place but of course there are lots of critters eating hair algae so that's easier to manage with herbivores.