Robelle 2110 Summer/Winter Algaecide for Swimming Pools, 1-Quart Non-Metallic Algaecide For All Pool Types (Vinyl, Fiberglass, Concrete, Gunite, etc.) Effective against all algae types (Green, Black, Yellow, Mustard, Pink) Prevents and Kills Algae Wait a minimum of 15 minutes after use Weekly maintenance dose: 32 ounces per 50,000 gallons