BBA is nature's way of telling us we don't have enough dissolved CO2 in the water for the amount of light we have. If you have tried doing a really thorough cleaning, and pruning to get rid of all traces of BBA, and it still comes back, you just don't have enough CO2 for the amount of light you have. You can either work on the CO2 or decrease the light.
I'm sorry Hoppy that is really not true IMO and impossible to even say. Are you saying co2 is an algaecide like Excel?