16 oz. Fountain Clear. This product prevents organic contaminates from forming (ie: crusty white scale deposits, iron, copper, hard water stains) using two uniqe technologies: one helps prevent the buildup of stains, and mineral deposits on the birdbath surface; the second uses bio-enzymatic activity to keep water clear and free from the organic debris that can make the water cloudy. For larger water fountains & indoor/outdoor waterfalls.