Possible Cause
Black algae
Solution
Use OXY-BRITE per directions. Add ALGIMYCIN 2000 or ALGIMYCIN 1000 as directed, then brush daily until gone. Use DROP ‘N VAC to help remove dead algae.
Preventative Maintenance
Use 8 oz. per 10,000 gallons of ALGIMYCIN 2000 weekly to prevent algae growth. Adjust returns to provide better flow over affected area.