Algaefix controls algae growth in ponds, water gardens, water features and fountains. Effectively controls: Green or green water algae (Chlorella) String algae (Cladophora) Blanket weed algae (Oedogonium) Once algal growth is under control, weekly doses will help control algae growth and reduce pond maintenance. Will not harm fish and plants when used as directed. Dosage: 5ml per 200 Litres of pond water.