About 6-7 years ago, I had an issue with some suspected Bryopsis. I bought a few gallons of Kent Tech M (magnesium) after reading about other treatments. I raised the Mag level very slowly to over 2000. (NL levels 1200-1440) The algae started to lose it‘s connection to the rock and I used a brush to twist it off easily. After that, the tiny bits were eaten by clean up crew and died off. The corals, fish, inverts, etc. all did well and I gradually lowered Mag levels back to normal with water changes. It took me about 1.5-2 months. The algae never came back. The only negative thing was that my super awesome Caulerpa in my refugium also died. It was a type of hard to find Caulerpa sadly and was fantastic for waste export. I wish at the time I had created another tank to save some of that algae. I just looked and I still have a gallon of the old version of Kent Tech M.