Robelle 2150 Concentrated Algaestroy 50 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: 2 or 3 oz per 10,000 gallons