BBA is more tufty. But it's really hard to see in the pictures. If it is bba you can spot treat with either excel or peroxide. If you do use the peroxide use an oral syringe and draw up about 3mls per gallon of peroxide and slowly squirt it on to the affected area. Make sure you turn off your filters and leave them off for roughly 20-30minutes. If you have a large area to treat you may need to treat 1 area a day until you notice algae turning colors. Usually red first when it's dying and then gray then white and it will slowing break down from there.
You will also have to figure out where it came from or it will be like putting a Band-Aid on a hemorrhage. What kind of lights do you have how and long are you running them? Do you use ferts? What are your levels?