BBA is black when it is alive, but red and white when it is dying or dead. The black algae on the leaf edges is, I think, BBA. So, I don't think it is dying from the CO2. Excel will kill it very well when dosed at 1.5 - 2X the recommended on the bottle dosages.

When I tried CO2 mist I found I had great pearling and plant growth, but BBA persisted unless I mechanically got rid of it and made sure the dissolved CO2 stayed up around 30 ppm. Like other algae BBA loves CO2. It just doesn't start its growth cycle if the CO2 level is persistently around 30 ppm day after day.