Bio-Dex Skill-It Swimming Pool AlgaecideSkill-it Algaecide is EPA registered and works with most common swimming pool chlorine and non-chlorine sanitizers to effectively remove and eliminate algae. It eliminates the majority of resistant colors and types of algae without causing staining. Its a user-friendly product that doesn't require adjustment to the water pH before applying. Skill-it Algaecide is an effective tool for fighting resistant, persistent algae over the long term. The product can be reapplied if the initial application doesn't completely eliminate the algae problem. Skill-it Algaecide can be added by itself directly to the pool water or water circulation equipment to eliminate algae. Skill-It Features: 50% concentration that kills and prevents algae Non-metallic formula that won't cause staining Removes all types of algae including persistent forms of algae Can be applied directly to the water Quart bottle (32 Ounces) Dosage Amounts: Initial Application or with algae present - Add 13 Ounces per 25,000 gallons of water or ratio thereof Maintenance Application - Add 3.3 Ounces per 25,000 gallons of water every 3 to 5 days or as needed such as after heavy or prolonged rainfall or when there is a heavy bathing load.