# How many plants does it take to control nitrate?



## tokyo (Jan 19, 2010)

First off, I would like to say that I am not looking to get around water changes. I still plan to do weekly water changes even if I get my nitrates to a stable zero. I just want to control my nitrates in an attempt to control algae and for the health of my fish.

And because I like these kinds of DIY projects. :thumb:

Anyways, onto my question...

How many plants would it take to control nitrate in a well stocked 55g? The plants I will be using are bacopa and I am also looking into getting some hygrophilia(possibly difformis). Which are fast growing plants, and therefore more efficient at removing nitrates than something slow growing, like java moss.

I plan on having a planted tank hooked up to the same sump as my 55g, this way I can stuff it full of plants and avoid putting any in my main tank(not that I don't like planted tanks, but I am keeping malawi mbuna and want to keep it rocky).

So what size tank would I need to have to house enough plants to control my nitrates?

Thanks!


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## adam79 (Jun 27, 2007)

I don't think there is a single solution. There are too many factors to consider. Plants are going to take in different levels of nitrate depending on light, co2, size, species, time of the day, ect. You may start out with a ton of small plants that keep your levels low, but as they grow you may need to add nitrate, so they don't starve.


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## tokyo (Jan 19, 2010)

Understandable, But I would like to have an idea of what size tank I should use. I can always remove or add plants later on, or add fertilizer if I need to.

I don't want to get all set up and find out later that I'm going to need more plants than will fit in the tank I chose.

I just want to make sure I have enough plants to control the nitrate.

I'm going to stay pretty low tech too, so no co2.

10 gallons would be the easiest size for me to work with, but I do have a 20g I could use too. Or I could always get someting bigger.

I was also thinking of maybe doing three 10 gallons next to eachother, but it would be a little bit more difficult to get everything hooked up correctly.

Any suggestions?


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## Fogelhund (Dec 3, 2002)

I keep a lot of plants in my African tanks, and have read quite a bit about keeping plants.

There are many variables, that makes giving you a straight answer very difficult. From the reading that I have done, a well planted tank, can support a couple of tetras, if there was no other method of removing waste. The plants will make a positive difference in a 55 gallon, well stocked with cichlids, but the plants alone will not be able to sustain the aquarium.


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## tokyo (Jan 19, 2010)

Fogelhund said:


> I keep a lot of plants in my African tanks, and have read quite a bit about keeping plants.
> 
> There are many variables, that makes giving you a straight answer very difficult. From the reading that I have done, a well planted tank, can support a couple of tetras, if there was no other method of removing waste. The plants will make a positive difference in a 55 gallon, well stocked with cichlids, but the plants alone will not be able to sustain the aquarium.


I will be doing water changes. So there will be a regular supply of fresh water. I just want to keep the nitrates down between water changes.

Do you mean that plants alone will not remove all or most nitrates?


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## LSBoost (Jan 21, 2010)

You might want to look into terrestrial plants. If you want nitrate to be at 0 all the time, I think it would take a forest in your house to do so. Anyways the point is the more plants the better, just my .02


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## tokyo (Jan 19, 2010)

How would you setup the terrestrial plants to remove nitrates from the water? Do you just submerge the roots in water instead of planting them in soil, or what?


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## adam79 (Jun 27, 2007)

Basically a fluidized plant bed. Have your filtration be the substrate and the plants roots will use the nitrate in the water. You could use semi-aquatic plants. This way the plants would use atmospheric CO2 and you could do more light. I think it would be more efficiant.


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## tokyo (Jan 19, 2010)

Thanks for the suggestion. I am really interested in putting together this setup. Does anyone have a link for more info about this type of setup?

Would bacopa be considered semi aquatic? They do grow out of the water.

Any idea what types of plants would be ideal for this setup?


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## LSBoost (Jan 21, 2010)

I'll post back a link for you on the plants if I find it later. I remember i ran across some.

Here's something for you to look at in the mean time  http://www.monsterfishkeepers.com/forums/showthread.php?t=180385&highlight=aquaponic

Oh a denitrator will work too.


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## emptyhead (Apr 16, 2007)

I keep a 55g planted tank that has 10 congo tetras and about 20 other small fish. The tank is heavily planted and I never really do water changes (maybe 2 or 3 a year). It is filtered by a Fluval 405.

Your filtration, bio load, plant level, and other bio area are all variables that make a precise answer impossible.

The general answer is - your tank has to be loaded with plants and you can't really keep large fish, if you are looking for a balanced ecosystem.


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## LSBoost (Jan 21, 2010)

Ok can't find the link but many people have success with philodendron.

Some other one that you may try are:
Peace lilies, Chamaedorea palms, Guzmania, vreesia, potho, corn stalk plants, vallis


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## DJRansome (Oct 29, 2005)

I have a 125G with like a dozen Vallisneria and one amazon sword smaller than my hand in it and I swear, I have to add nitrate to keep from getting cyanobacteria (triggered in this case when plants are dying due to lack of nutrients.

I think the Vallisneria (maybe just contortionist like I have) are really fast growers and heavy feeders. To achieve a better balance I'm planning to switch them for more plants that grow slow and steady.


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## tokyo (Jan 19, 2010)

Thanks for the link LSBoost. That setup isn't as attractive as using plants, but if its as effective as they say it is I may have to try it out! Plus its pretty compact which is perfect for me since I am quickly running out of room for all my DIY projects. 



adam79 said:


> Basically a fluidized plant bed. Have your filtration be the substrate and the plants roots will use the nitrate in the water. You could use semi-aquatic plants. This way the plants would use atmospheric CO2 and you could do more light. I think it would be more efficiant.


Is there a name for this type of setup? I'm trying to find more info on it but without much luck. would it be considered to be a form of hydroponics? What sort of filter media would work for this setup?


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## Darkside (Feb 6, 2008)

Look into refugiums.


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## fox (Jun 11, 2009)

DJRansome said:


> I have a 125G with like a dozen Vallisneria and one amazon sword smaller than my hand in it and I swear, I have to add nitrate to keep from getting cyanobacteria (triggered in this case when plants are dying due to lack of nutrients.


Same here.

20 gallons of plants works for me. I just recently tore down a refugium with 8 gallons of plants as my nitrAtes would rise to 40ppm each week on a 65 G tank. I set it back up with ~ 20 gallons of refugium and got 10 ppm nitrAte creep after three weeks on a 210G tank with a bunch more fish load.

I have been using different plants over the last 5 - 6 years since tinkering with fuges and have settled on low light low maintenance plants since I will still be doing WC's anyways.

I believe , though I have no proof, that plants take away more than just nitrAtes since the tanks I use refugiums with have healthier and more colorful fish and a cleaner water collumn.


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## LSBoost (Jan 21, 2010)

*Fox* I also have good experience with plants. I think they make my water super clear. I don't even have fine filter pads in my filters.


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## tokyo (Jan 19, 2010)

I read an article in a TFH magazine about a hatchery that used plants as their filtration on a closed circuit system. The water turned to be much clearer than any of their other systems. This is one of the main reasons I decided to start looking into plants for function rather than just aesthetics.


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## adam79 (Jun 27, 2007)

tokyo said:


> Thanks for the link LSBoost. That setup isn't as attractive as using plants, but if its as effective as they say it is I may have to try it out! Plus its pretty compact which is perfect for me since I am quickly running out of room for all my DIY projects.
> 
> 
> 
> ...


I'm not sure if there is a name for the setup. I can't even remember where I got the idea. A few years back I had a heavily stocked 125 gallon tank with large predators that wouldn't allow any plant to live. I wanted to help lower my nitrates, so I wouldn't need to do ridiculous water changes. My plan never made it past paper, so I can't say it would even work, but this is it.

Build a wooden planter box that was the length of the tank and 1/3 the width and approx 9-10 inches deep. This box would mount on the back of the tank. The inside of the box would be painted with pool paint(the same stuff people use in plywood tanks). One end would be plumbed as the inlet and connected to a prefilter(most likely a canister filter). The other end would be plumbed into the tank. The bottom 2-3 inches of the box would be filled with gravel, covered with cotton filter media, and then toped with soil and planted. Ofcoarse, you would need some good lighting in addition.


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## tokyo (Jan 19, 2010)

I've been doing alot of research on hydroponics and what system would work best for the result I want. I decided that NFT(Nutrient Film Technique) would work best for me because it encourages rapid growth which would mean my plants would be alot more efficient at removing nitrates and phosphates. Basically a NFT system is a system where there is no soil or growing medium. The plan roots hang into a container that has a regular flow of nutrient rich water on the bottom and a large gap between the plants and the water. This makes the roots have to stretch down to reach the water leaving part of the roots exposed to the air. Allowing much more oxygen to be absorbed.

I am modifying the system a little so that it will included inside a sump. I will have the front half of the sump reserved for my "filter box" a heater and my return pump. Then in the rear half I will have a set of sponges that reach up to the bottom of the plants so that the roots will grow down these into the water.

I also recently discovered that this whole idea of using plants to control waste in a closed circuit aquarium is a well established idea called aquaponics. There are all kinds of good setup designs out there. I'm only just starting to learn about it, but it seems to be pretty similar to my modified hydroponics idea.

Wikipedia defines aquapponics as "the symbiotic cultivation of plants and aquatic animals in a recirculating environment"


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