During that 24 hour period while the chlorine level in the water is so high brush the surfaces at least two more times preferably three or four times to get any remaining black algae off the walls and floor of your pool.
Removing black algae from pool walls.
Black algae generally penetrate porous pool surfaces like concrete and gunite.
Black algae is a thread like growth that develops on rough surfaces in swimming pools.
Black algae have deep roots that work their way into.
It appears as dark black spots on the walls and floor of the pool and is slippery to the touch.
Yellow and black algae will require a heavy brushing of pool walls and floor while green algae may only need a light brushing.
Brush daily for a week with the proper brush for your pool paying special attention to algae affected areas.
Once these surfaces are infested with black algae it will take time and persistence to eliminate it.
Brush all the surfaces inside your pool.
For yellow and black algae it is a long process and cannot be achieved in a day or two but for green algae you may solve the problem in a matter of hours.
Those pesky little spores stick to the cloth and hop off in the pool the first chance they get so be sure to use bleach to clean them.
Black algae can get into your pool several ways but one of the most common is from swimming suits that have been in the ocean.
The protective layer that forms on black algae makes the algae otherwise impervious to regular sanitizers so you must brush the algae to break through this layer so that chlorine and algaecides can kill the organism.
This type of algae forms in a layered structure with the outermost layer protecting the lower layers.