Two months after the massive pruning of the Bucephalandra caterina and the Anubias nana ‘Pinto’ in an effort to control the black beard algae (BBA) that was colonising them, the battle is lost. Further, inspection showed the BBA had thoroughly colonised the Cryptocoryne parva as well.
I have come around to thinking of BBA as a symptom rather than a problem – in other words the BBA indicates something is wrong that needs to be addressed. In this case I believe it is a build-up of organic waste in the aquarium, and also perhaps the natural life cycle of some of the plants. The caterina was planted 2.5 years ago and the parva 2 years ago where a gradual loss of fitness means they have a hard time fighting off algae.