# A couple of questions



## Caeru (Dec 26, 2009)

Continuing to get good plant growth in my 10g. I'm thinking about adding some plants in a week or two.
My LFS has a lot of Vallisneria Spiralis and Micro Swords. Has anyone here had success with these in a low light setup? My 10 gallon has one 15w florescent strip, but sits in front of a window so it gets a good amount of sunlight.

My second question is kind of weird. What about a bare bottom floating plant only tank. Do the floaters rely on nutrients from the substrate, even though there not IN the substrate? I threw some extra hornwort clippings in my 10 gallon bare bottom tank that is currently cycling with a regular HOB filter, and it exploded. I've got some duckweed on its way in the mail to toy around with too. I'm sure you couldn't establish a true low-maintenance (no water changes) aquarium this way, but has anyone tried something like this? How do floating plants work?


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## mudboots (Jun 24, 2009)

> Vallisneria Spiralis and Micro Swords. Has anyone here had success with these in a low light setup?


I've seen these in lots of pics and mentioned on lots of posts as being good for those conditions.



> How do floating plants work?


They are SUPERB at cycling a tank. Being exposed to the surface, they have an endless supply of CO2, hog all the light to prevent algae outbreaks, but allowing low light plants to grow if you thin them out once in a while, and their roots remove all the excess nutrients, waste, toxins, et cetera from the water column. Theoretically, you could have a floating plant-only tank (with fish of course) and never really need to change the water out; just make sure they get what they need (lighting, nutrients via feeding et cetera...). The respiration rate (assuming it's a complete canopy) would be such that you'd be adding water pretty regularly, and thinnings would prevent buildups in the concentrations of heavy metals et cetera...

All that said, I have never tried it, so I could be way off base, but there's quite a bit of available research to get you started in the right direction.


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## NatalieT (Mar 20, 2007)

Barebottom with floating plants: something like that is working for me as a quarantine tank right now. It's got the water surface covered with salvinia and some random floating bits of stem plants, and I threw some java fern in the bottom--that's largely to help the fish feel more secure. It's a ten gallon tank, but I've had 17 fish (mixture of otos and cories) in there for almost 2 weeks now--it looks like it would be pretty stable as a long-term thing. The fish and plants seem healthy, and I'm positive the floaters have been growing and spreading.

I tried it because I needed to set up something fast, so I threw in the plants that were easiest to grab: the ones without proper roots. It's worked so well, I'm sure I'll be repeating it in the future. Of course, I'll be able to take it down just as easily as I set it up--put the plants back in another tank, dump out the water, and put the tank away for another time.


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## dwalstad (Apr 14, 2006)

Caeru said:


> I'm sure you couldn't establish a true low-maintenance (no water changes) aquarium this way, but has anyone tried something like this? How do floating plants work?


Plants purify water for fish such that water changes are less necessary. Also, fish stay healthier (my book _Ecology of the Planted Aquarium_, Chapter II, 'Plants as Water Purifiers')

Floating plants have many advantages over submerged plants, so they remove nutrients/potential toxins more quickly (my book, Chapter IX, 'The Aerial Advantage')

Hornwort does not qualify as a floating plant (it is a rootless, submerged plant), but it still can greatly help to purify the water. One fish breeder uses it to purify water for raising Angelfish commercially (my book, p. 27).


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## Diana K (Dec 20, 2007)

Even though Hornwort does stay pretty much under the water (mine grew so much it sort of pushed itself up into the air a little bit) I will suggest that being so close to the surface these plants (Hornwort and other plants that stay submerged, but right at the top of the water) also get a better than average supply of CO2, because they are so close to the air/water interface. Gases do not move too fast deeper into the tank, but with the plants so close to remove the CO2 quickly from the near surface water, more CO2 can enter the water faster than average, so perhaps not a true aerial advantage, it is not far from it.


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## ObiQuiet (Oct 9, 2009)

I've been using an Eclipse 6g as a Q tank, with floating hornwort, duckweed and one Amazon sword in a tea cup.

Although the tea cup has soil+substrate, the hornwort and duckweed have begun to need more nutrition (after about 2 months with no fish).

Last week I started adding main tank WC water and fertilizers to this Q tank. I expect the floating plants will pick up again soon.

-ObiQuiet


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## mudboots (Jun 24, 2009)

Just out of curiosity, what size tank are you proposing as a potential floating-plant-only tank? This will help determine what to use. Ie, water hyacinth would be great in a large, deep tank with it's massive, cascading roots, but overpower a medium to small tank; Azolla, frogbit, red-root floater, lemnas, salvinias...all really nice for smaller tanks and all quite efficient at nutrient uptake and storage. But in a floating plant only tank you'd definitely want some root mass hanging in the water at least a little bit.


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## Caeru (Dec 26, 2009)

Thank you all for the great info!

My duckweed came in the mail yesterday. I put waaay too much in, and it ended up clogging my filter over night. I took a good portion of it out today. I plan on making a barrier around the water flow with some plastic from a 2 liter coke bottle to prevent the duckweed from floating into the stream and getting knocked down into the water (thus getting sucked up into the filter). I think that should fix it.



mudboots said:


> Just out of curiosity, what size tank are you proposing as a potential floating-plant-only tank? This will help determine what to use. Ie, water hyacinth would be great in a large, deep tank with it's massive, cascading roots, but overpower a medium to small tank; Azolla, frogbit, red-root floater, lemnas, salvinias...all really nice for smaller tanks and all quite efficient at nutrient uptake and storage. But in a floating plant only tank you'd definitely want some root mass hanging in the water at least a little bit.


I'm using a 10 gallon tank. I will definitely look into getting some of those small size floaters your mentioned.


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## mudboots (Jun 24, 2009)

> ... it ended up clogging my filter over night...


Very interesting; you may want to get one of those Whisper or other in-tank filters that you can lower to where the outflow is even with the water level to prevent the down draft. I have floaters in both a 125 gallon (a salvinia species) and a 3 gallon (Azolla caroliniana), but neither tank has a filter on it (the 125 has unfiltered water movement via a Koralia pump), so I'm not sure I'm offering the most sound info. I've a similar filter in a 10 gallon, but it's only got 6 or so gallons of water, and the in-tank filter is really only there to provide water movement across the rocks that are stacked up out of the water.


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## Caeru (Dec 26, 2009)

I guess my main concern is that I have one medium sized fancy goldfish in the bare bottom 10 gallon. Goldfish create a larger bioload then most fish and I'm afraid to take away both the mechanical and biological filtration that the aquaclear provides. This may be just the old, non planted aquarium me being paranoid about meeting gallon per hour/biological filtration requirements. This whole live plants thing is really starting to change my perspective. 

On the plus side; since I've added the duckweed, the goldfish has been more happy and active then I've ever seen him. He LOVES to graze on it (though depleting it doesn't seem like it will be a concern). He's not interested in the hornwort.

If I took the goldfish out and put some less demanding fish in, I would be open to a lower flow rate, or maybe even filterless tank.

Any thoughts?

Edit: To clarify, I have 2 separate 10 gallons. One is bare bottom, the other is soil substrate and fully planted.


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## Diana K (Dec 20, 2007)

Keep up the filtration for the Goldfish. Move the Gold into increasingly large tanks before he seems to need it. They grow BIG and they grow FAST. 
Keep the tank pretty close to full so the water flow from the Aquaclear sheets across the surface, and does not create a strong force down into the water. Yes, it can drive enough duckweed down that way to clog the intake. Redirecting the water flow with a bit of plastic works, too. 

Bare bottom with floating plants will be fine for the Gold, but keep the filter going. 
Many Golds tend to dig, some more than others. I would not try the Gold in a planted tank with really fine substrate. I think the water would develop a permanent cloudiness. If you want to keep a Gold in a tank with a substrate I would use gravel (about 1/4" diameter, 1" deep max) and plant in pots with gravel on top of the soil. Driftwood with plants like Java Fern and Anubias tied to it are good, too.


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## Caeru (Dec 26, 2009)

Yeah, the goldfish will be re-homed in a 29 gallon I have lying around once he gets too big...unless I go nuts and turn that into another low-tech planted haha... I'm trying to refrain until I've proven that I can get some good sustained growth in my current one.

I wouldn't dream of putting him into my soil substrate 10 gallon. He would tear it apart I'm sure. Plus, my betta is quite happy in there. 

It'll be interesting to see how adding the duckweed, hornwort, and whatever other non-rooting plants I happen upon (I was eying some water wisteria today at the store) effects the frequency of water changes in my goldfish tank.


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