Ideal for helping to prevent green pond water and a great pond algae treatment. NT Labs Pond Aquaclear controls algae, algae bloom and blanketweed by filtering out light. It restricts algae growth using a UV screening, faint blue dye. Aquaclear was voted the Gardening Which? 2007 Best Buy Winner for Algae Control. For best results we recommend using in conjunction with Magiclear - however both will work independently. 250 ml treats 14000 litres (3132 gallons)