how are the three tanks set up? are they running as one system or are they all seperate? everything thats been listed will help rid cyano but the more important thing would be to try and find the reason why your getting so much of it and having algae issues in all three tanks. the bryopsis can usually be taken care of by dosing magnesium.get your water tested to see what the mag level is at. i believe that running the mag between 1500-1600 (double check these numbers) will get rid of the bryopsis. i started getting it in my frag tank and bumped the mag up and havent seen it since. but for the rest of the issues, I would go back to square one. check the flow of every tank make sure the current is strong, check your lighting, maybe the bulbs need replacing (if using bulbs) or maybe cut them back a couple hours. are you running a skimmer at all? make sure you have a skimmer that is rated for the total water volume you have. if you have an ro filter make sure the filters dont need to be replaced and check how long its been since the membrane was changed. cut back on feedings well. especially if the food your using is very rich, this will pollute the water more. and if my memory serves me correct, wernt you carbon dosing using mb7? ive heard from many people that were using that to carbon dose that even though there levels were near 0 or 0 that they were still having algae problems which comes from having to small of a skimmer running on there system to begin with and trying to carbon dose. sorry that was long. bottom line is until you find the source of your problems your going to be spending all your time fighting algae then getting to enjoy your reefs. good luck and hopefully you can get a handle on the algae.