Waterlife Algizin G resolves green water problems which prove a major challenge for pond keepers throughout the Spring Summer Autumn. Algizin G works by flocculating the green water (clumping it together) and causing it to drop out of suspension. After Algizin G has achieved this the algae is removed by pump or filtration. Algizin G is safe with all pond fish and plants and will not damage filtration bacteria.Treatment may be repeated after 7 days if necessary or when the water shows signs of turning green again. 125ml bottle - treats up to 9000 litres.