i am sure this has been recommended already but i have had great success in beating/battling bryopsis with the addition of the following: sea hare (dolabella a.) , lettuce nudibranch (elysia c.), pitho crab, emerald crab.
had a single rock in my DT overrun with bryopsis at one point. added the sea hare and lettuce nudibranch and it was it cleared within two weeks (the sea hare died due to nutrient spike), lettuce nudibranch got caught in my nero 3 wavepump. i then purchased 2 pitho, and 2 emerald crabs from reefcleaners and i have not seen any sign of bryopsis in my DT (except on top of my return nozzels). currently, i have bryopsis in my fuge and it is choking out my chaeto to death. i bought an emerald crab for my fuge, and am waiting for pitho crabs to come back in stock at reefcleaners to buy another. my emerald crab would go from my fuge chamber to my skimmer chamber and hide there, so i have to constantly drag him back to the fuge section. hope that's not the case with the pitho crab i plan to buy for my fuge..