Yes if it is on the older leaves, just cut them off.. It all depends on what sp. of rodophyta you got in there BBA is just a collective name of a rather large family.. In my case the one roaming in my low tech tank is kinda light sensitive, so going down with light intensity helps a lot to slow it down and go away.
Now that going away is just a way we perceive it. Once this algae is caught, it stays latently present even if you do not see it. There is no need for panic, it is rather common to have. It also is a typical BBA propperty to affect old (unhealthy) leaves from slow growing plants.
In my own experience with my 2 low tech tanks, i see light beeing the main BBA accelerator.. Especialy in low tech tanks with easy and slow growing plants we rather tend to have to much light intensity compaired to the grow speed of the plants. What works best for me is extending the periode and lower the intensity.
In a way it's only logical, plants need light to grow, now when it comes to slow growers low light plants. Giving them a short period of 8 hours higher intensity and 16 hour darknes, doesn't make much sense, it doesn't make them grow faster. On the contrary they still grow slow, it's in their nature and this for a shorter day periode.. So the short periode of excess light that the plants doesn't utilize is not making a plant healthy and in many cases only feeding algae. Giving them a longer period of less intensity keeps them growing for longer periode. And in the end this will only result in more plantmass over the same time span.
Anyway both my low tech tanks have 12 hour + light, the one with the lowest intensity has 0 BBA. The other just a little, but this tank receives a bud load of daylight. With this i'm still searching for the best combination between the 2 light sources available.
I've learned this from my outdoor pond, that in the summer receives 18 hours of daylight for months and about 12 hours full sun and it never has BBA and very little other algae.. Only thing i do is grow plantmass and block light intensity with floaters.
If this works in nature, than i have no clue why it would be a problem with an indoor aqaurium and what the idea is behind higher intensity short light periodes above a low tech.
We all can agree, we need light to make plants grow, not darkness..