Personally I feel Co2 is part of it, but is it the biggest part of keeping BBA and other algae away? Why is the water change so essential to keeping things pristine? Pretty simple to me your diluting any nitro organic decay, but at the same time your creating fluxing co2 levels are you not? If you increase water changes to every day are you going to get more algae because of the constant co2 flux. I don't think so.
The control for that is simple:" use activated carbon(AC), same for allelopathic chemicals, add AC. This removes those organic chemicals effectively.
Do we see less BBA in tanks where they use AC? Purigen?
You can also add organic forms of N, say more fish, more fish food etc. Or add NH4, say urea or NH4Cl.
I've done it and postulated a long time ago that NH4 was a potential inducer for Green water. But I was able later to add 0.8 ppm per day of NH4Cl without any Green water or algae blooms.
I tried fish loading, progressively adding more and more bait minnows till I got a crash, GW, followed by staghorn and finally some BBA. About 100 3" bait minnows ina 25 Gal tank with foreground rug plants only. A stemy planted tank would require a lot of fish for this to occur.
I think works more like this:
If you switch to Daily water changes then this becomes more stable(CO2).
If you do it say one day a week, then it's less stable. Daily water changes works pretty well with CO2. Dose after etc, we do this a lot when there are "issues" and it does tend to fix many "issues". Folks experience excellent growth post water change day.
It's those days in between that cause issues if the CO2 is poor.
I do 2x a week for some tanks, once a week for others, once a month for some. Generally based on how much pruning/moving weeds around I do and light umols. Fish loads are quite large for all 3 tanks.
CO2/very high light tank has the CO2 around 55ppm. A couple of Hair algae issues.
CO2/mid light(180) has CO2 about 70 ppm. Virtually no issues.
CO2/low light 70 Gal, no issues, CO2 is about 50ppm.
O2 is 7 ppm to about 9.5 ppm depending on time of day.
Every so often, the CO2 will run out and I'll not notice or catch it for 1-3 days etc. Plants seem okay with this overall, algae not an issue, if you go a week etc, then?
The other issue I had when using disc and some diffusers: they did not add enough CO2 in the start of the day cycle. If i measured later in the day, I had ample CO2, if I measured every 15 min from light= 0, till light on for 2 hours, I had much less.
In other tanks, the built in overflows degassed too much to keep up with the CO2 delivery system. I would gas fish or not have enough CO2, very hard to balance that. Adding a bean animal or other type of prefilter made this issue go away.
Still, all these things tend to get back to CO2. It's(CO2) not a simple thing.