Duckweed

[SteveM]

Hi everyone.
Duckweed question. Ive got a pond and a tank with persistent duckweed issues. The tank I can keep on top of manually, but the pond is 16x10 feet, fed using half EI doses, and that's a battle I don't think I'm going to win. Been looking at a few treatments. NT labs do a chemical one, Ecopond do one based on bacteria, and my LFS shop reckon a light misting with glyphosate will kill it without harming the fish/inverts. Needless to say I'm VERY wary about the last one, but I wonder if anyone has any experience of using any of these. Don't want to kill everything.
Any advice greatly appreciated.
Cheers
Steve

 

[Ria95]

can't say i have. In general if it affects Lemna it will affect other plants. Some have used light sprays of H2O2 on the affected surfaces, in this way it's a more directed approach. Have you tried using a pond surface skimmer? One that would allow duckweed to get in may be useful. The one from Tetra looks like it could be adapted for this purpose. In the aquarium setting, a surface skimmer and a little work will get rid or it.

 

[mort]

Hi, what fish do you have in there and how old are they? Im going to assume goldfish/koi and they are brilliant at eating duckweed, you can get them to do so by feeding less in spring. I don't use chemicals so I'd try removing as much manually as you can and then giving the fish a chance.

 

[SteveM]

can't say i have. In general if it affects Lemna it will affect other plants. Some have used light sprays of H2O2 on the affected surfaces, in this way it's a more directed approach. Have you tried using a pond surface skimmer? One that would allow duckweed to get in may be useful. The one from Tetra looks like it could be adapted for this purpose. In the aquarium setting, a surface skimmer and a little work will get rid or it.

Read about a skimmer, thought I could build one from a bucket and some foam. Do you have a link for the tetra one? Is it this one? In-Pond Skimmer | Tetra®