just adjust co2 accordingly. slowly
u don't HAVE to adjust the lights,, but reducing them does decrease the need for co2.
adding more co2. will NOT remove or kill bba. it has to be manually removed. do so with vigor and keep it controlled. it will spread easily.
after manual removal. if co2 is correct it iwll not continue to grow
UNLESS u have very few plants. having lots of plants does help