Hydrothol® 191 Granular with alkylamine endothall is a selective, rapid-acting, contact herbicide and algaecide. Controls submersed weeds and algae in lakes, ponds, irrigation canals, and drainage ditches.

Works rapidly enough to be effective in both still and slow moving water. May be harmful to fish at recommended application rates.

The physical form, mode of action, and general usage of Hydrothol® 191 Granular are similar to Aquathol® Super K. Where fish are present application of Hydrothol® 191 Granular at rates over 1.0 ppm should be used only for spot treatments, narrow margins, or where some fish kill is acceptable. Do not treat more than 10% of a lake or pond at one time at application rates above 1.0 ppm.

When treating lakes or ponds with Hydrothol® 191 Granular begin at the shoreline and work toward the center. Apply parallel to the shoreline. This will herd fish away from the treated area into deeper untreated portions of the lake or pond.

As little as 0.2 ppm of Hydrothol® 191 Granular will control algae when an entire pond is treated. For longer term control or spot treatments use 0.5 to 1.5 ppm. Repeat treatment when growth reappears. For floating mats scatter uniformly over the surface of the mat. Weeds growing in lakes or ponds will require application of 0.5 to 2.5 ppm of Hydrothol® 191 Granular.

Heavily infested irrigation canals or drainage ditches will require 3.0 to 5.0 ppm of Hydrothol® 191 Granular.

To determine lbs. of material to use for lakes or ponds multiply the application rate in ppm by 5. This will give the number of lbs. to use on 1,000 sq. ft. at an average depth of 4 ft. Adjust quantity of material up or down depending on average depth.

To determine lbs. of material to use for irrigation canals or drainage ditches use 1.25 lbs. per 1,000 lin. ft., per sq. ft. of cross section, per ppm. For a 2,000 ft. canal, with a cross section of 15 sq. ft., at 3 ppm use: 1.25 X 2.0 X 15 X 3 = 112.5 lbs.

Water treated with Hydrothol® 191 Granular should not be used for irrigation or human and animal consumption for 7 to 25 days depending on the application rate. Fish from the treatment site should not be consumed for 3 days.

Most effective against: submersed Weeds - Specifically: Pondweed