# duckweed driving me nuts!



## helenf (Mar 24, 2008)

To all those duckweed lovers out there: how do you not get it all over everything all the time?

I have duckweed in my new 5 gallon NPT. I think I need it because it is supposed to be such a good grower and the water has high phosphate (presumably from the potting mix I used), which I'm hoping the duckweed will deal with in time. And its the only thing getting carbon from the air rather than the limited amounts in the tank, since none of my potentially emergent plants are tall enough to emerge yet.

But so far the duckweed isn't growing that well, nothing like the "doubles in 3 days" thing that I have read it can do. And I feel like I have to save every little bit of it, so I spend ages, every time I have to fiddle with that tank, rinsing the duckweed off my hands and any equipment, so it isn't lost from the tank. It's a hassle! 

I have good southern-window daylight (southern hemisphere here, so a southern window doesn't get as much light as a northern window, and no sun at all) coming in the top and side of the tank, plus a 14W compact fluorescent bulb in a normal desklight over the tank. Can I expect the duckweed to start growing well enough that I don't need to worry about losing bits every time I touch the tank? 

My ideal would be to be able to put my hands into the NPT and rinse the duckweed off into the goldfish tank nearby. But to do that, I'd have to have the duckweed growing fast enough that I didn't just lose the lot that way. 

I have thought about trying azolla instead. Is that easier to handle than duckweed? I think the leaves are bigger, aren't they, so maybe they wouldn't get stuck to everything quite so easily? 

How do you duckweed lovers out there cope with your duckweed?


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## yum (Feb 11, 2008)

It can get really annoying as it snags onto the taller plants and clumps up. But I usually have to just brush it to the sides so I have a clear spot of water to feed the fish.

I look at the duckweed like I look at my exploding snail population: food for my dad's tank. The extra duckweed feeds his silver dollars and the snails for his clown loaches.

My neighbor asked me for some of my guppy fry to feed his cichlids but I couldn't bear the thought.


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## bartoli (May 8, 2006)

helenf said:


> But so far the duckweed isn't growing that well, nothing like the "doubles in 3 days" thing that I have read it can do.


Reducing water surface agitation will promote duckweed growth.


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## Red_Rose (Mar 18, 2007)

I had first gotten Duckweed in July when I had an ammonia spike in my 10g. It came off of the Water Lettuce. It grew rather slowly until October and then it just took over the tank!

I use to like Duckweed when it didn't grow quickly but then I was removing a ton of it every week so I got rid of it. I've been Duckweed-free since November and my betta likes it much better without that in there! The roots were getting so long(3+ inches) that it was starting to irritate him and I was annoyed at how quickly it grew. Not only that but whenever I would trim down my plants, the Duckweed would be all over it when I pulled the plants out of the water! I never bothered to save the stuff that I pulled out with the plants though. If I wanted it back, I just had to wait a day or two and it would've grown back again. 

If you want a good fast growing floater then I suggest finding some Riccia fluitans. I don't recall hearing any complaints about that plant. Or you can grow Wisteria as a floater too. I had an extra stem or two from the bunch I bought for my 2.5g and I didn't want to just rely on my Hornwort so I snipped the Wisteria stem in half and dropped it into the tank as a floater. Tomorrow will be one week since the tank has been set up and the Wisteria has some lateral shoots and even some roots are forming!

I've never had azolla but from the pictures I've seen, I wouldn't mind trying a bit of that but if you really want to give Duckweed a try, I just recommend being patient with it. I'm sure it'll start taking over your tank in no time.


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## Angie (Dec 4, 2005)

I love my duck weed, so does my tank and my goldfish. lol


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## mommyeireanne (Oct 24, 2007)

I like it in the tanks that don't have a HOB filter. The one with a HOB sends it all over the tank- stuck in all the plants. Not a combination. I am ordering Water Lettuce (Pistia startiotes) which is big and will hopefully starve off my algae. 
I started with a tablespoon in Feb, in three weeks I had enough for all the tanks and had to start removing some. My regular tanks don't get direct sunlight, just their bulbs and a bright room. I still like it, just not with hang on the back filters.


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## newbie314 (Mar 2, 2007)

I have it and no filter.
Actually on my 2.5g the duckweed isn't growing at all.
Maybe time for a bulb change, since it has been a year.


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## helenf (Mar 24, 2008)

bartoli said:


> Reducing water surface agitation will promote duckweed growth.


There is no surface agitation at all - no filter or powerhead in the tank. It's only a 5 gallon tank, so I am trying to get by without a filter.

You know, the duckweed is looking, I think, like there's more of it this morning. Maybe my new light (the 14W CF desklight is new to the tank since 3 days ago) is working...

Red_Rose: thanks for your comments. Maybe it is the wrong time of year for duckweed to be growing well here (in AU), since its past the end of the summer. I'll try being patient and see what happens. I've love to be able to feed my goldies with the stuff on a regular basis.

I have read that duckweed roots get longer when there is less nutrition in the water, as they search out every available piece of food. Maybe that's why your roots got so long? Mine are less than 1 inch so far, but I don't mind if it gets longer, as I'm partly using it to deter fish from jumping out of the uncovered tank.


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## mommyeireanne (Oct 24, 2007)

Red Rose: do you have the bigger or smaller version? I think mine is the smaller (Lemna minor), I might like the longer roots. Mine stay at about 1/2 inch.


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## Red_Rose (Mar 18, 2007)

mommyeireanne said:


> Red Rose: do you have the bigger or smaller version? I think mine is the smaller (Lemna minor), I might like the longer roots. Mine stay at about 1/2 inch.


I had the Lemna minor in my tank. I would've liked the larger forms of it but I have yet to see any of the other types of Duckweed in garden/fish stores.

My betta would flick himself against the roots of the duckweed. It's like he was trying to tell me to get rid of it! lol Once I cleared it out of the tank, he was fine.



helenf said:


> I have read that duckweed roots get longer when there is less nutrition in the water, as they search out every available piece of food. Maybe that's why your roots got so long? Mine are less than 1 inch so far, but I don't mind if it gets longer, as I'm partly using it to deter fish from jumping out of the uncovered tank.


I'd agree but the thing is, not all of the roots were very long. Some stayed small whereas others got very long. The rest of my plants were growing in well so I don't think it was because of lack of nutrition.


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## mistergreen (Mar 3, 2007)

You can fish net those things out... make sure to do it everyday, incase you missed the first time.


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## helenf (Mar 24, 2008)

Fish net which things out?

I want the duckweed in! I just don't want it to be such as hassle  (might be dreaming the impossible dream, here)


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## Raul-7 (Feb 4, 2004)

helenf said:


> Fish net which things out?
> 
> I want the duckweed in! I just don't want it to be such as hassle  (might be dreaming the impossible dream, here)


Actually contrary to popular belief, water circulation will promote the growth of duckweed! I conducted a study on _Lemna sp._ last semester and found out that a little water circulation is better than no circulation at all.


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## NatalieT (Mar 20, 2007)

I don't think you need to worry about saving every single piece of the duckweed--if there's enough to get stuck on your hands, there's enough to grow more, too. I've got both duckweed and salvinia minima as floaters in my tank, and I find the salvinia easier to deal with. The leaves are a little bigger, which makes it easier to avoid taking them out by accident, and also easier to remove them when there is too much.

Natalie


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## cturner (Jan 9, 2008)

Sorry I have to reply to this one! I started with a little bit of duckweed in my 90g with no co2 after many months I still seemed like I had the same amount (still does to this day, 6 months later). Anyhoo, I set up a 20g long and used some plant clippings from my 90g to get it started and apparently I got some duckweed into the plants I transfered over and now 4 months later the top of my 20g is covered in duckweed. The 20g has co2 and an aquaclear on it. The shrimp love to hang upside down on the roots.


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