WEEDTRINE-D is a broad range herbicide that controls duckweed, coontail, elodea, naiad, pondweed and milfoil. Weedtrine-D can be sprayed on or simply poured from the container. Results often begin to show in as little as 3 days. Two week water restriction. Dosage rate: Duckweed 5-7 gallons per acre, submersed weeds 8-12 gallons per acre.