Duckweed control is a frog friendly duck weed treatmentduckweed control contains a specialist bacterial culture which removes nutrients key to the growth of the most common species of duckweed lemna minor so that once existing weed has been removed its return is inhibitedduckweed control will not harm fish wildlife or other plantlife in the pond500ml treats ponds up to 4500 ltrsinitial doseone full measure from dosage chamber per 450 litresmaintenance10ml per 450 litres weekly