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Sonar A.S. Aquatic Herbicide Concentrate

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  • The most effective aquatic herbicide in controlling duckweed and watermeal.
  • This concentrated formula (41.7% Fluridone) can control many aquatic weeds with just one application for a year or longer.
  • Effective against many aquatic weeds, such as American Pondweed, Bladderwort, Coontail, Curly Leaf Pondweed, Duckweed, Eurasian Watermilfoil, Hydrilla, Elodea, Sago Pondweed, Southern Naiad and many more!
  • Please Note: special Sonar A.S. return/exchange policy and use restrictions below.
Shipping Restrictions!

Due to state and local regulations, we cannot ship this product to AK, CA, CT, DC, HI, ME, NJ, NY, PR, RI, VT, WA or Internationally.


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Sonar A.S. Return/Exchange Policy: Sonar AS is an effective, concentrated, restricted use herbicide that ships direct from the Manufacturer; SePro, Inc. and therefore cannot be returned or exchanged after purchase. Your order of Sonar A.S. is guaranteed to be delivered safely and intact. Thank you for your understanding.

Sonar A.S. is one of the most effective aquatic herbicides on the market for controlling duckweed and watermeal in fresh water.  It uniquely provides multi-season relief so you can enjoy your pond's clear natural beauty. Sonar A.S. is a selective, systemic, root killing herbicide, which means it targets weeds while allowing desirable plants to remain. While this product is highly concentrated, it carries no water restrictions on human swimming or consumption.

Sonar can also control many other aquatic weeds such as: American Pondweed, Coontail, Cattail, Hydrilla, Elodea, Spatterdock and many more!

Available in Sizes

  • 16 oz. - treats up to 0.5 acre
  • 32 oz. - treats up to 1 acre
  • 128 oz- treats up to 4 acres

Application Instructions

  • Shake the Sonar A.S. container well.
  • Refer to the container label to mix the correct amount of Sonar A.S. with water in a tank sprayer. For example, use 19.5 fl. oz. (45 parts per billion) to 39 fl. oz. (90 ppb) of Sonar A.S. per treated surface acre if your pond has an average depth of 5 ft.
  • Spray the Sonar A.S.-water mixture beneath the pond's surface at a volume of 5 to 100 gal. per acre.
  • Spray only 1/4 to 1/3 of the pond at one time if the weed infestation is heavy because dying plants reduce oxygen in the water, which is dangerous for fish.
  • Remove dead debris with a rake as needed.
  • The herbicide's effects on plants usually are visible 7 to 10 days after treatment. Complete kill can take 30 to 90 days.
  • For watermeal control, Sonar A.S. must be used at the highest recommended label rate.
  • Do not exceed a Sonar A.S. application total of 90 ppb per annual growth cycle.
  • For best results, apply Sonar A.S. early in the season, prior to or just after plant growth begins.

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