I had BA REALLY bad about two years ago. The first thing I had to figure out was; what was the issue allowing BA to take over. For me it was feeding too much and not being consistent with my nutrient export. I had to do the following to get it under control (in order of what I think worked the best):
Took out my rockscape (where I could) and scraped off as much BA as possible followed by a quick h2o2 bath.
Fed less food (we feed our fish too much anyways!)
Increased the flow in the tank significantly.
Increased skimmer to wet-skim until BA got under control. I have mostly a softie tank so they like the water to be a bit dirty.
Increased my photoperiod of my refugium and removed chateo on a regular basis. Before I would let it just keep growing and growing.
3 emerald crabs.
In the end I eradicated about 95% of the BA and don't have an issue anymore. As long as you find the sweet spot for nutrient export BA will have a hard time taking a hold of your tank.