HELLO back. Not sure about all the yelling in here so listen close to make sure you can here me over that noise.
First note: raising Mag with a standard magnesium supplement has a very low success rate with Bryopsis. Use Kent Tech-m brand as there is an additional component that makes it work.
Second note: there are a few fish that sometimes help with this issue. They are not 100% however so your mileage may vary. The one's that I have had success with include Foxface rabbit fish, Rainfordi goby's, copper banded butterfly.
With the exception of the goby the other fish have risks that you should know about before putting them into a reef setup. Mainly specialized diets or a like for other sea life that may be in your tank. They may be worth looking into though to see if they might help you as well.
Edited by Krazie4Acans - November 10 2015 at 1:41pm