how to Keep duckweed under control

[bloom]

Duckweed is taking over my 20 gallon tank, it's covering the surface completely. I've got a sponge filter, moderate lighting, and do weekly water changes. How do y'all keep it in check without nuking the whole tank?

[gunsmoke]

Manual removal is the only way. Scoop it out daily with a fine net. Duckweed reproduces fast, so you gotta stay on top of it. I run a high flow canister filter to keep the surface agitated, slows it down a bit.

[oceanstar]

I've found that reducing light exposure helps. Duckweed thrives under bright conditions. Try shortening your photoperiod to 6 hours and see if that slows the spread.

[bronzo99]

Yeah, duckweed's a pain. I let mine grow wild in my shrimp tank, but in my main display, I gotta scoop it every other day. Goldfish love munching on it though, so maybe get a couple if your setup allows.

[handan]

Introduce floating plants that outcompete duckweed, like Water Lettuce or Frogbit. Their larger leaves block light and roots absorb nutrients faster. Works in my 40 gallon with CO2 injection.

[bloom]

Thanks for the tips, folks. Gonna try reducing light first and see if that helps before adding more plants or fish.

[Rythmix]

Manual removal is the only way. Scoop it out daily with a fine net. Duckweed reproduces fast, so you gotta stay on top of it. I run a high flow canister filter to keep the surface agitated, slows it down a bit.

I agree, but it's such a chore. I've got a turkey baster I use to suck up clumps, way easier than a net.

[pipero]

Duckweed's a beast, man. I gave up and let it run wild in my betta tank. The little dude loves hiding under it, and it keeps nitrates low. Win win, I guess.

[zenfly]

If you're gonna manually remove it, do it before water changes. Less chance of it spreading when you're already disturbing the water. Also, check your ferts, duckweed goes nuts with excess nutrients.

[blackiron]

Surface agitation is key. I pointed my HOB filter output slightly upward to create more movement. Duckweed hates it, but my other floaters are fine. Just gotta find the right balance.