Sonar: A Safe and Simple Herbicide

Sonar can be poured anywhere into the pond and will diffuse out throughout the pond in the course of 30 days with dramatic results in 3-6 weeks.

By  •  • 4 minute read

Sonar A.S. is another herbicide from the Sonar family at SePro. SePro is the largest manufacturer of aquatic herbicides in the world, and we have the honor of being certified by SePro to apply their herbicides.

Thanks to SePro, homeowners can enjoy the benefits of time-tested application methods and materials developed by SePRO scientists. SePRO is recognized as the world leader in advancing the science of aquatic plant management. It is very safe, simple to use and it treats floating and submerged aquatic weeds all season long. There are a few other “Sonars,” but Sonar A.S. claims to be the most potent.

Sonar A.S. Aquatic Herbicide is a 41.7% fluridone based aquatic herbicide that effectively kills most lake and pond weeds in freshwater ponds, lakes, reservoirs, drainage canals and irrigation canals. The fluridone doesn’t kill the weeds when it’s applied; it interrupts their process of photosynthesis by starving the aquatic plants which keep them from growing. It provides broad range control on submerged and floating plant species including Duckweed, Water Lillies, Watermeal, Watershield, Naiad, Eurasian Watermilfoil, American lotus, and most other pondweeds.

It does not have to be sprayed. It can be poured anywhere into the pond and will diffuse out throughout the pond in the course of 30 days with dramatic results in 3-6 weeks. It slowly kills the aquatic plants, so fish kills aren’t a problem. Sonar A.S. is very thorough, and it covers a lot of territory killing lots of different plants in a pond- particularly ones that have turned kind of into a jungle or wetland.

Sonar A.S. gives the most efficient concentration level and is the ideal choice in ponds and lakes with the least amount of water flow. Rapid water movement or any condition which results in rapid dilution of Sonar A.S. in treated water will reduce its effectiveness. Sonar A.S. is soaked up from the water by the plants and from hydrosoil by the roots. Maintaining the specified concentration of Sonar A.S. in contact with the target plants for a minimum of 45 days is important for in-water treatments.

In receptive plants, Sonar A.S. suppresses the arrangement of carotene. When there is no carotene, chlorophyll is quickly degraded by sunlight. Herbicidal signs of Sonar Genesis appear in seven to ten days and look like white (chlorotic) or pink growing points in many plant species.

One of our more recent members, Andy, is a homeowner with a 6-acre pond. He called us about a Duck weed problem and asked how he could make his pond beautiful again. All the neighbors can see it, and it was becoming an eyesore. He was also nervous that if he didn’t get a grip on it now, it would continue to get worse and end up costing him a fortune. We told him that is how it normally goes and if ponds and lakes are left uncared for, or even if they just aren’t cared for properly, it can be very costly in the end.

All he needed to do was make the decision to become a member to ensure his pond would stay beautiful and healthy; but if he didn’t, aquatic plants would take over resulting in high-cost projects. Andy decided to become a member so he could keep his pond healthy and beautiful. We used Sonar A.S. to clear the duckweed. The duckweed drank the liquid Sonar and began to die. He quickly noticed results and was proud of his pond again.


  • Sonar A.S. gives broad range control on submerged and floating aquatic plant species including Duckweed, Watermeal, Water Lillies, Watershield, Naiad, Eurasian Watermilfoil, American lotus, and most other pondweeds. DIY and purchase Sonar

  • Very Expensive.

  • You will see dramatic results in 3-6 weeks.

  • Not for use in hydroponic farming, or in water for irrigating nursery or greenhouse plants.

  • Algae (Chara, Nitella, and filamentous species) are not controlled by Sonar A.S.

  • Rapid dilution due to water flow will reduce results. Best results occur in ponds with little or no outflow.

Taking care of your lake or pond is not a luxury, it’s a necessity. As your local pond management professionals, we’ve been there. Let us help guide you as a member to protect, plan, and preserve your pond or lake if you live in the Charlotte NC, Asheville NC, and Greenville SC areas.

Get started. Become a member today!

Filed in: Aquatic Herbicides , Algae Aquatic Weeds , Pond Management , Lake Management & Charlotte, NC • Tags: Aquatic Plants , Aquatic Herbicides , Pond Management , Lake & Charlotte NC

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