I used kent tech m for my issue in my 75g. I took it up to 2000ppm and held it there for 1 month. The bryopsis died at about 3 weeks and I slowly let it fall back to normal levels the bryopsis did not come back. I also tried the BRS stuff and it didnt work but I only had it to about 1600ppm before I ran out and found out that like Beakerbob said it needs to be above 1800ppm to properly kill the bryopsis.