Black algae - Black Brush algae / Audouinella

Audouinella is also called aquarium black algae, found and widely spread in marine and freshwater environments.

This black algae looks like a bunch of hair with black, brown or red color, grows on solid surfaces like rocks, stones or the edges of hard & slow-growing leaves. Algae eaters don't like this kind of aquarium algae, one way to remove the eyesore is by pulling it out and scrubbing the surface - it can ruin the leaves. Anyway, the spores are still out there and can germinate any time if the environment allows it.

It is already tested by varying the level of nitrate (NO3) and phosphate (PO4) in planted tanks, but the result didn't show any significant change in development and new growth of the aquarium black algae. But again, aquarium CO2 concentration in planted aquariums is the consistent and major inducement for this aquarium algae, enough CO2 level stops the algae bloom.