BBA is not related to ferts normally. Well, according to one of those articles BBA can be caused by various factors, like too much Ca compared to Mg(your rocks), excessive phosphate, etc...
In a not planted tank the best way is to clean it manually as BBA won't die on it's own. Clean the filter media in tap water, do several bigger water changes in a row and you can also get a small bottle of Excel and just dose the recommended dose for a period of time as Excel is algecide and helps kill the BBA.
In the article I posted the owner suggests removing certain types of rocks but in a cichlid tank it's not a good idea. You can decrease the intensity of light though.
In a not planted tank the best way is to clean it manually as BBA won't die on it's own. Clean the filter media in tap water, do several bigger water changes in a row and you can also get a small bottle of Excel and just dose the recommended dose for a period of time as Excel is algecide and helps kill the BBA.
In the article I posted the owner suggests removing certain types of rocks but in a cichlid tank it's not a good idea. You can decrease the intensity of light though.