How many plants do you need to put in an aquarium to make a
significant dent in nitrates?

We all know plants use nitrates as a food source, but I have 4 potted
plants in my 20-long aquarium and the nitartes do not seem to be any
less. Is it that I need to put a truckload of plants in there to
reduce the nitrates or what?

Right now only my monthly water changes do anything, and I'm not
looking for a way to stop doing water changes, it's just that I don't
want them getting too high because it promotes algae and is bad for
fish.

Frost

From my (limited) experience, if you have a lot of plants it wont
necessarily remove nitrates. Think of it as a recipie, you need ALL the
nutrients for plant growth for the plants to use the nitrates. In other
words, if you dont have enough of one nutrient then the plants wont look at
the other ones cos they need them all. Kind of like a nutrient bottleneck

I think for any noticable nitrate reduction due to plants you need some
really fast growing plants. Ive got some plants in my tank that seem to be
growing an inch every day or so. I use co2, 11 hours of light a day, trace
element fertiliser and potassium. Check out the krib website for fast
growing plants and a way to do a nifty little co2 system for a few
dollars/pounds

Mark

"Paul" wrote in message
om...
How many plants do you need to put in an aquarium to make a
significant dent in nitrates?

We all know plants use nitrates as a food source, but I have 4 potted
plants in my 20-long aquarium and the nitartes do not seem to be any
less. Is it that I need to put a truckload of plants in there to
reduce the nitrates or what?

Right now only my monthly water changes do anything, and I'm not
looking for a way to stop doing water changes, it's just that I don't
want them getting too high because it promotes algae and is bad for
fish.

Frost

Is it that plants absorb ammonia faster so you end up getting less nitrates?
I have about 70% plant mass in my tank and notice a difference. I don't
think 4 potted plants would do anything, IMHO. Maybe add floating plants
like frogbite, don't have to worry about algae and they take up nutrients
fast.
"Paul" wrote in message
om...
How many plants do you need to put in an aquarium to make a
significant dent in nitrates?

We all know plants use nitrates as a food source, but I have 4 potted
plants in my 20-long aquarium and the nitartes do not seem to be any
less. Is it that I need to put a truckload of plants in there to
reduce the nitrates or what?

Right now only my monthly water changes do anything, and I'm not
looking for a way to stop doing water changes, it's just that I don't
want them getting too high because it promotes algae and is bad for
fish.

Frost

On 28 Sep 2002 22:01:43 -0700, (Paul) wrote:

How many plants do you need to put in an aquarium to make a
significant dent in nitrates?

I guess it depends on the amount of fish in the tank. Any plant will
consume a little of the nitrate. The more plants, the more nitrate
they will use.

But, just having lots of plants isn't enough. The plants need to
growing fast, so that they are using the nitrates as fast as they are
produced. Typically, that is done with CO2 injection and high light
levels, and lots more plants, of a fast growing variety.


Chuck Gadd
http://www.csd.net/~cgadd/aqua

Mark Trueman wrote:

From my (limited) experience, if you have a lot of plants it wont
necessarily remove nitrates.

Of course there are many variables, but I have 71 community fish in my 72
gallon, heavily planted tank, and Nitrates still measure well under 10ppm. I
have to ADD 0.5 ppm nitrates per day to keep Nitrates in the 5-10 ppm range,
otherwise plant growth slows and Nitrate measures under 5ppm.

Once plants get well established, all forms of Nitrogen are history!

On Sun, 29 Sep 2002 12:58:43 -0700, "Greg" wrote:

Is it that plants absorb ammonia faster so you end up getting less nitrates?

Partially. Plants will use ammonia, and also nitrate. Both forms of
nitrogen are used by the plants.



Chuck Gadd
http://www.csd.net/~cgadd/aqua

I think that any significant reduction of nitrate to plants because you need some really fast growing plants. I am doing some plants in my tank seems to be growing about an inch a day. I use carbon dioxide, 11 hours a day, light, trace elements and potassium fertilizers. Check out the krib rapid growth of the plant site and do a nice little way of CO2 system a few dollars / pounds

In Ecology of the planted aquarium, Diana walstad outlines how it is possible to keep water well within the peramiters for keeping aquarium fish without water changes or filtration, but simply with plants and a high bioload.
this is done with fast growing stem plants aswell as heavy root feeding adsorbing neutrients from the substrate and oxygenating the substrate preventing too much matter rotting within the substrate.
she also freely admits that it dosent always look that pretty, especialy when the watter becomes full of tannins released from breaking down plant matter.
I have known several people who have tried this "natural approach" and failed drastically losing entire fish and plant stocks. In reality there are 3 ways to deal with the nitrate cycle in a fish tank.
1) low fish stock, highlevels of filtration, daily fertilisation, a neutrient rich substrate. and heavily planted. The highlevels of filtration mean more ammonia is processed by the filter bacteria than is adsorbed by plants meaning that when you test for nitrate when fertilising you get an accurate measure. and can ajust your fert routine according to the levels of niterate existing in the water column.
2) Denitrification equipment, There are various systems available some chemical some utilise bacteria. when i had a marine tank I successfully built a denitifyer that kept nitrates at 0. i had a 6ft long length of drain pipe capped at each end. I carefully coiled many many many meteres of 6mm air hose around the indise of the pipe leaving a gap up the middle. this was then filled with bioballs before the end was sealed.
the principle was that bacteria would adsorb all oxygen from the water on its way down the air tube and then denitryfying bacteria would take over and produce nitrogen gases thusly removing all nitrate from the water column.
3) Regular water changes and cleaning debris from your tank. Prevents nitrates building up and is the most simple and cost effective way to deal with the tank. I do mine weekly