Tsunami DQ Aquatic Herbicide- Quart - 37.3 Percent Diquat Dibromide – Concentrated Aquatic Weed Killer for Lakes and Ponds - Duckweed, Watermeal, Curly Leaf, Pondweed & Many More

Stuff works and best price for it is Amazon. You have to reapply it im a month or two if thick moss on top but worth it cause it really works. Saved our pond from suffocation.

it works amazing for top surface weeds. But it doesn’t kill the root. Reapplying will eventually kill the weeds

This stuff is a little pricey, but you don't need much per batch so it will go a long way. I used it on dry ground. Works very well. The directions say to completely cover the target and that is what I did. Any plants not covered completely will still survive.

Seems to kill surface weeds well, have not noticed any subsurface weeds dieing , weeds were heavy, going to spray again

I think this is a good value. I've used this on pond and land weeds. It has great knock down power but doesn't kill roots. However it kills any vegetation it contacts in 24-48 hours. My pond was 99% covered in Duck weed! We'd been treating with copper sulfate every 2 weeks and it still came in and took over. I spray this as soon as I see new growth. New growth slowed down and finally stopped. Need a 1 1/2 stronger solution than the instructions for aquatic. Duck weed is tough stuff. Use surfactant too. And it didn't hurt the fish. I also always use a glove and mask, etc. Better to be safe.