Thanks for all the info. A) So I'm lead to belive BBA colonizes when CO2 is deficient or when it's levels are inconsistent. B)Also if the plants are growing and doing well, then there will be no black brush algae colonizing. From my encounters with BBA, I could see both of those hypotheses being true.
A few general observations: In a tank with no supplemental carbon and very high light, I had no BBA until I did water changes with city tap water. The more water changes I did, the more this stuff would colonize, but if used RO water, I had no more colonizing. Based on what I've read here, I would imagine the tap water was high in CO2, and the temporary rise in CO2 spurred the BBA colonization.
Regarding B) generally when the plants are growing really well, the BBA is not spreading. Now is this because the CO2 levels, and/or perhaps the tank conditions are stable and therefore the stimuli for BBA to colonize are not there, or is there some sort of allelopathic effect that is only generated by growing plants that keeps the algae from colonizing? I was reading through an awful planted tank book a few months ago, and that was one of the nice sentimental points the book made (healthy plants will produce allelopathic chemicals that inhibit algae), which I have not seen talked about much outside that book. Since the book had so much misinformation I have to think that Idea could be bogus as well.
Finally my last mixed question/statement. Would the build up of CO2 at night, if you run it 24/7, promote BBA colonization?
Oh one more, has anyone looked into the life cycle of the BBA? Anyone know the Latin name? I'm guessing there are some spores being exchanged, and probably some environmental cues that trigger their development and release? If we knew exactly how this stuff operated we would have a much better chance not getting it in the first place.