Add Swamp Treat™
Add one (1) bottle of Swamp Treat™ per 20,000 gallons of pool water.
Brush the walls of the pool. You’ll need to get as much of the black algae off the surface as possible, so some scrubbing might be needed.
Add approximately 2 pounds/gallons of shock per 10,000 gallons – cascading it around the pool.
Set your system back to filter, and turn the pump on. Allow to filter for 24 hours