Hydrothol Granular Herbicide and Algaecide

A fast-acting granular contact herbicide and algaecide used to control submerged weeds and algae in lakes, ponds, and irrigation canals. It is especially useful for targeted dock and shoreline treatments.

Active ingredient

11.2% mono(N,N-dimethylalkylamine) salt of endothall.

Product details & application

• Granules sink into the treatment zone for bottom-growing weeds and algae.
• Controls submersed weeds and filamentous algae simultaneously.
• Treat heavy vegetation in sections to reduce the risk of oxygen depletion.

Key plants / growth controlled

• Chara
• Spirogyra
• Pithophora
• Hydrilla
• Elodea
• Coontail
• Milfoil
• Naiad
• American pondweed
• Sago pondweed
• Curly-leaf pondweed
• Water stargrass

Application examples

• Lakeshore 100 ft × 100 ft: 55.89 lb
• Lakeshore 75 ft × 100 ft: 41.31 lb
• Lakeshore 50 ft × 50 ft: 15.58 lb
• The supplied guidance notes a 20 lb bag generally treats about 2,000–8,000 sq ft depending on rate and target.

Water use & safety

The supplied information states there is no swimming or fishing restriction immediately after proper application, but treated water should not be used for irrigation, drinking, or livestock watering for 7–25 days depending on dosage. Do not use in ponds with koi, grass carp, or goldfish at rates that can be toxic.

Shipping restrictions

Cannot ship to: AK, CA, CT, HI, ID, ME, MA, NH, NJ, NY, RI, VT, WA.

Important: Always refer to the current product label for exact application rates, restrictions, directions, and instructions.