Sonar RTU (Ready-to-Use) Aquatic Herbicide - 1 Quart Systemic Herbicide for Duckweed, Hydrilla and Most Difficult Aquatic Weeds, No Equipment Needed, Simply Pour in for Season Long Control

I have a small backyard koi pond of approx. 800 gallons that got duckweed a couple of years ago from some plants I had ordered on eBay. This product is expensive but I hadn’t found a better option, so I bought a bottle and did the math to determine that I needed to add a whopping 3 ml. I double checked my work and got the same answer. So I used a syringe that had come with an inkjet refill kit, shook the bottle, sucked 3 ml out, and squirted it into the pond. It remained kind of congealed so I did mix it into the water. A week later and the duckweed turned light in color and started to die off. I skimmed most of it off and it’s obvious that it is no longer spreading. I’ll reapply in a couple of weeks per the directions but I stand amazed that 3 ml was this effective. It does not appear to be affecting my 3 koi at all.

This stuff works. Finally something that cleaned our pond up. I am very happy with this product. It has taken me years to find something that works like this and doesn't harm the fish.

This did not work for us. We did it exactly as directly, completed 2 cycles and our pond is still a layer of green duckweed. We even used bacticlear with it. Disappointed because I thought we had found an answer and spent a lot of money for nothing. I wish we just saved the money and spent it on a pond company who guarantees removal

My 1st review ever here. When I tell you my pond was inundated and ruined with algae and duckweed the last 5 years…this product WORKS!! Have patience with it, clean your pond while it does its thing. I can only smile while my pond is back (clear) and beautiful for this summer ☀️

Finally, after 40 days the duck weed is gone! After my first application (1 quart for a 1/4 acre pond) the duck weed grew faster and multiplied like crazy. I thought surely I was feeding the duck weed and not killing it, but I call the company that make this product and they assured me the Sonar was going to work but I had to be patient and let it do it's job and BINGO, after 40 days the duck weed was gone. I am thrilled!