Well I'm sorry to say that you will not win this battle unless you rid the tank of the problem. The problem isn't the algae, it's what is causing the algae to grow. You have to clean your water so the algae doesn't have to. You can kill the algae with mag, pull it out, cook it, but it will keep coming back until your water quality is better.
You first want to make sure you are using good 0 TDS water so that you are not adding anything during water changes and do a large water change. I've seen phosphates in water with 0 tds so make sure you test your new salt water for phosphates to make sure you are not adding them that way. Second you need to get a reactor running with good GFO and Carbon. If you can't get that reactor running then get some GFO/Carbon in a filter sock and stick it where as much water will flow through as possible. If you have a skimmer then run it a bit on the wet side. You also need to get some algae growing in a place you don't mind it such as a refugium, cheato or algae scrubber. If you don't have a refuge then get some algae that would be ok in the display. Once all this is done then you can start removing/killing the bryopsis/bubble algae either manually or with mag, but not until you fix the other stuff.
