Crank your CO2 up a notch by 5-10ppm more...you are likely to be still low on CO2. Monitor the behaviour of your critters and if they are fine, you can add more up to 10+ppm or so. Remove what is left of the old BBA and you should not see any more new BBA growth if the CO2 is good. New folks who uses ADA aquasoil always seems to have issues with poor CO2 level due to the peat influence. I really don't know why they like it except for the colour though.