If it is BBA, it will turn into a relatively cute looking black fur - long fur, but not long like hair algae. Think cat fur. Anyway.
The best way to deal with it is get hold of some Flourish Excel and a 1ml baby syringe. Turn your filter off and remove any activated carbon. Use the syringe to spot-treat the algae with the Excel. Leave the filter off for an hour afterwards.
Within a few days you should see it shrinking, turning red and dying right off. :) I used to have a huge amount on my anubuias and this deals with it really well. :)