For aquarium hobbyists, black brush algae are definitely disturbing. They grow on the surface of woods, rocks, and aquarium plants particularly. By spraying glutaraldehyde or hydrogen peroxide, we can kill black brush algae which are visible for naked eyes. Yet, the zoospores hiding from our eyes can only be dealt with UV or ozone. Adding glutaraldehyde periodically seems to suppress the growth of black brush algae.
Besides black brush algae, is there any other organism killed during the process?
I took some black brush algae growing on the CO2 diffuser. It looks like there's nothing else living on them.
Here's the photos shoot under high magnification of light microscope. We can see there are lots of organisms living on the black brush algae, such as diatoms and rotifers.
Ecosystem of an aquarium is more complicated than we can imagine.