Sanco Step 4: Tsunami DQ Aquatic Herbicide Diquat formulas of this non-selective herbicide effectively kill submerged and floating pond weeds Works on duckweed, water meal, water hyacinth, pondweed, slender leaf pond weed, coontail, and more The diquat dibromide (37.3%) herbicide can be blended with other herbicides for many uses Use at a rate of 2-8 quarts per surface acre depending on infestation and aquatic weed type Classified as state-restricted in CT, MI, NH, NJ and NY