A complex long lasting, non-foaming algaecide specifically formulated to control black algae and other resistant stains in swimming pools. It can be added at any time. It will control recontamination by algae because its active copper remains in solution for an extended period of time. Initial dosage: 12 oz. per 10,000 gallons. Maintenance dosage: 6 oz. per 10,000 gallons, every 5-7 days.