Black Beard algae
The most common issue with folks that have BBA seems to be one
surrounding CO2 levels. Often folks with DIY are plagued. A few with
gas CO2 but it's far less common generally.
If you can maintain a 20-30ppm range of CO2 for the entire light
period, am to pm, then you will likely not have any issues with new
growth. Doing this might not kill wahat is there, but if the algae
stops growing, then you have it beat.
Adding a good amount of CO2 will help the plants grow faster and
better and maximize the available nutrients they need to grow and also
it maximizes the light you use as well.
You can use, as suggested, bleach dips for slow growing tough leaved
plants to kill what's there, or trim them or a combination of both.
Fast growers easily outpace the BBA.
Test your pH in the am and the pm and see what the CO2 levels are at
these times. Try and get the CO2 to be 20-30ppm for this entire
You'll also see a marked increase in peraling and NO3/PO4 uptake etc.
Some folks on the APD did some test on BBA and we tried all sorts of
things, but limiting it never worked, good plant growth and good CO2
levels did and at least stopped it.
Mild cases can be solved with SAE's, trimming etc.
If you follow Diana Walstad's or my modified version for non CO2
methods, you will likely never get it in a non CO2 tank.
By taking a good look at the CO2 and making sure there's enough for
the plants, no matter what, this will help the plants grow better.