I think your BBA may be due to your non-CO2 and 2wpg - too much light.

Blackouts don't work on BBA, nor most algae.

Have you tried the overdosing Flourish Excel method? I fear that this will only be a temporary measure though.

You need to solve the cause of the BBA and inject CO2.

I have personal experience of Excel, you may be able to use this instead of CO2 but it will work out more $$$, and probably less effective.