The blackout has minimal effect on brown algae. Blackouts are generally good for blue-green algae (cyanobacteria) and mild green water.
To remove the brown algae, invest in some more oto's and maybe Amano shrimps. You can always remove it yourself using a soft sponge - gently. This is a tedious process but then you can remove it ALL in one go if you are patient.
In regards to the lunar blue LEDs at night:
Plants require light during the day for photosynthesis and they DO NOT require any form of lighting at night (like us, when we sleep!) so that is one reason to not add additional lighting at night. Secondly, fish want darkness at night so that they can 'sleep' also (again, like us), lights just distract them and keep them 'awake' causing their energy to drain etc (once again, like us!).
I would stick to lighting during the day (8~ hours) and no lights at night. Not even the small LEDs you want.
Best of luck,