just wanted to share H2O2 worked very well for me. I had a massive growth of bryopsis and other algae which is rapidly taking over my tank and killing my corals. I tried many approaches over 3 months but could not stop the on slaught of the algae from taking over. I then tried dosing H2O2 which worked to rid the other algae at the recommended dosage but the bryopsis seems to be able to cope. Finally, I decided I will need to either restart my tank or take a higher risk to rid the bryopsis which will not go away.
*WARNING* I am just stating my personal experience so please understand there are real risk involved.
I did a system wide dosing of 250ml at one shot to my 100 litre/25gal tank. This works out to be about 10ml per gal. There was massive bubbling throughout the tank. All the corals shrunk and looked very bad for about an hour. It did kill all my snails and my RBTA. Lots of bristle works came out of the LR and floated to the top which I removed promptly. The corals slowly recovered after one day and guess what? It was a complete wipe out of all algae in my tank and my tank is slowly making a very good recovery. It's been 3 weeks since I did the massive H2O2 does and there's still no algae of any kind in the tank.
So perhaps there's hope for desperate reefers like me . . .