BBA is entirely caused by unstable co2. If you have reflectors on your lights spin one round to block the light from the tank, drop you light period to something more reasonable like 6 hours (8 should be about your max when the tank is running well), increase co2 injection, increase flow and distribution, increase water changes and spot dose the BBA with liquid carbon. It looks like you can remove the plants easily, if so then you can make a liquid carbon bath for the plants (not moss) in a 5ltrs of water add about 40ml of liquid carbon, dip the plants for about a minute or two then put them into a bucket with clean water. After rinsing add them back to the tank, BBA will go pale or pink and then fall off, you still need to do all of the above otherwise it will only come back.
A solenoid will also help stability. How are you injecting co2?