Use algae preventers regularly to prevent algae growth year round. In order for preventative algaecide to be effective, it must be added in sufficient quantity before algae has formed and the level must be maintained. Initial dose must be 8 to 12 oz. per 10,000 gallons of pool water, followed by a maintenance dose of 4 to 8 oz. per 10,000 gallons every week. Additions should be made directly to the pool the day after shocking.