Stop doing water changes.
Add a SAE or two.
If you have a high bioload, reduce it.

Read the non CO2 method I suggest here.
Trim the BBA off the plants, remove the grains.

The stopping of the water changes will solve most BBA related issues in non CO2 methods.

Excel will work to get rid of things but you need to get rid of water changes and root causes.

Light is fine, but you could likely also stand to add more plant biomass.

Regards,
Tom Barr