The plants are doing great!!!! The BBA is a pain..... I have a 30 gallon Cube it's 18 in deep I have 15 live plants I cannot gravel vac because I use aquavitro plant substrate like a mud the light fixture is a finnex 24/7 CC SE, I have it specially program for Me. so it is not on 24/7 it is on currently from 9 to 6ish. it was on from 6 to 6 and I cut it back in half cuz the Black Beard algae starting to grow from 9 a.m. to 12, it is on red light only 12 to 3 it is on from white & Green, and from 3 to 6 it is purple. the light fixtures specific RGB. What plants need to grow.It doesn't look like BGA to me.... Looks like BBA and GDA along with some hair algae.
How long are your light on? What size tank (height too)? what model lights? Dosing any fertilizers or CO2? Water change schedule? Lots of mulm in the bottom of the tank? Clean filters regularly?