# Duckweed control



## l33tgeist (May 8, 2011)

Hello all, it's been a while since I've posted here. Things have been going so swimmingly that it hadn't really occurred to me to think about it too much. However, I find myself with a minor but growing annoyance now, for which someone here may have a solution. As the title suggests, the duckweed is out of control. I clear 70% it out every week, and by next week its back, shading out all the plants and generally making a mess. 

My tank is heavily planted, by which I mean it's just about solid plant from front to back, top to bottom, and side to side, and over all of this craziness is a thick layer of duckweed, tangled up with the other floating plants in a way that makes it quite a hassle to completely remove. 

I have diy CO2, I throw some general-purpose organic land-plant-fertilizer into the filter about once a week, and there's medium-high light for about ten hours a day. I think phosphorus is the limiting nutrient in my system, because there's a lot of green spot algae and my Java Fern doesn't grow nearly as fast as the other plants. I'm thinking about getting some additional high-phosphorus fertilizer for the water column, but I'm concerned that this would further encourage the duckweed. 

Suggestions? Should I just be more thorough and painstaking in my mechanical removal of the stuff? Should I get some particular type of fish to eat it? Competition with other plants is clearly not doing the trick. Do I just live with it?


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## fishtk75 (Sep 6, 2006)

l33tgeist said:


> Hello all, it's been a while since I've posted here. Things have been going so swimmingly that it hadn't really occurred to me to think about it too much. However, I find myself with a minor but growing annoyance now, for which someone here may have a solution. As the title suggests, the duckweed is out of control. I clear 70% it out every week, and by next week its back, shading out all the plants and generally making a mess.
> 
> My tank is heavily planted, by which I mean it's just about solid plant from front to back, top to bottom, and side to side, and over all of this craziness is a thick layer of duckweed, tangled up with the other floating plants in a way that makes it quite a hassle to completely remove.
> 
> ...


I had the same problem and the only way I got all of it out was use a net and turkey baster. Use the net for large cleaning and small areas I suck them out with turkey baster. The floating plants take out and pick out the duckweed if you have the time. I did not do that with my floating plants I throw them out.
after two weeks I had no more duckweeds.


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## Michael (Jul 20, 2010)

Goldfish.


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## l33tgeist (May 8, 2011)

I'm seeing that goldfish, rosy barbs, and american flag fish all eat duckweed, but they all prefer significantly lower temps than the 80 degrees in my tank. Any true tropical fishes that will do the trick?

I'm hoping to avoid the turkey baster, but that's always a possibility.


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## Lakeplants (Feb 21, 2011)

Duckweed thrives in warm temperatures and high-nutrient conditions, so as long as you're providing those conditions, your duckweed will colonize the tank quickly. The goldfish might be ok in 80* water. Otherwise, the simple net-removal technique always works to thin it out. If you thin it to a greater degree, it will take longer to fill back in.


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## Willfull (Nov 9, 2011)

Point the output of your filter towards the surface of the water and keep netting it out. Do this daily and eventually you will get it all. Add some congo tetras to finish off any stragglers.


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## xxbenjamminxx (Oct 18, 2011)

I seen this elsewhere and thought it looked pretty slick. Others claim it works great and looks like it would work awesome. Maybe trim down plants so they arent to the surface and set this up in there for a couple hours here and there.






Hope this helps you!


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## neilshieh (Jun 24, 2010)

you will have to use a net and just net it all out and then pick out the rest. there's not other way.


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