Blagdon (formerly Interpet) Duckweed Buster : Controls the spread of unsightly DuckweedDuckweed Buster is a natural bacterial product which prevents the growth of Duckweed (Lemna Minor) by modifying the water chemistry and creating conditions which prevent the spread of this problematic aquatic plantDirections:Easy Dose BottleInitial Dose : 25ml for every 450 litres of pond waterMaintenance Dose : 10ml for every 450 litres weekly until duckweed is no longer visibleThis product cannot be overdosedAn eco-friendly pond product : harmless to filters and all species of pond fish, other pond plants and water using wildlife