# Nitrogen Deficiency



## aclaar877 (Feb 19, 2014)

A properly cycled aquarium with "good" bacteria will convert ammonia into nitrate. I don't know if it can revert back - I've never heard of it doing so. 

Plants need nitrogen, potassium and phosphate in comparatively larger amounts, plus trace elements in smaller amounts. Nitrogen deficiency often appears as deteriorating older leaves, often yellowing of leaves, as the plant "feeds" off older growth to put out new growth. Most people shoot for 10-20 ppm nitrate (NO3) in planted tanks, though you can go higher and be fine. To address deficiency you need to add some. Most use a fertilizer (KNO3, potassium nitrate), but in lower tech tanks fish waste may be enough. Tap water sometimes has a little nitrate in it to begin with.


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## rpadgett37 (Jan 2, 2014)

aclaar877 said:


> A properly cycled aquarium with "good" bacteria will convert ammonia into nitrate. I don't know if it can revert back - I've never heard of it doing so.
> 
> Plants need nitrogen, potassium and phosphate in comparatively larger amounts, plus trace elements in smaller amounts. Nitrogen deficiency often appears as deteriorating older leaves, often yellowing of leaves, as the plant "feeds" off older growth to put out new growth. Most people shoot for 10-20 ppm nitrate (NO3) in planted tanks, though you can go higher and be fine. To address deficiency you need to add some. Most use a fertilizer (KNO3, potassium nitrate), but in lower tech tanks fish waste may be enough. Tap water sometimes has a little nitrate in it to begin with.


Ok. So for the sake of clarification, A nitrogen deficiency refers to insufficient nitrate in the water. The role ammonia / ammonium plays in it is in it's ultimate conversion to nitrate. Is that right?


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## chris_ranger (Mar 17, 2014)

If i always test for nitrates and come up 0 or close to it should I dose nitrogen? I dose everything but nitrogen.


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## greaser84 (Feb 2, 2014)

chris_ranger said:


> If i always test for nitrates and come up 0 or close to it should I dose nitrogen? I dose everything but nitrogen.


I would dose nitrogen in your case, it sounds like your plants are absorbing nitrates faster then your fish can make them. The goal is to never run out and hovering around 0ppm could be a problem down the road. I suggest you calibrate your test to see what your really at, because those test can be off. http://www.plantedtank.net/forums/showthread.php?t=83545&highlight=calibration

OP: This is how it goes ammonia will be converted to nitrite, nitrite will be converted to nitrate that's it, it won't convert to anything after that. This statement is correct A nitrogen deficiency refers to insufficient nitrate in the water.If you have a nitrogen deficiency the plants will stop growing and will not take up any other nutrient until nitrates are introduced again. You can never have multiple deficiencies, once one is missing growing halts. What I see a lot is someone has a deficiency and continues to add ferts but the one they are missing, they don't realize that the ferts they are adding aren't being used, that's where algae takes over.


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## aclaar877 (Feb 19, 2014)

Yes, if you want to grow plants they need nitrogen. In a cycled aquarium, ammonia will be converted to nitrate. If you have little ammonia, then you'll get little nitrate from it.


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## Zapins (Jan 7, 2006)

rpadgett37 said:


> What exactly is a Nitrogen Deficiency?


A nitrogen deficiency refers specifically to the damage that happens in plants when there isn't enough nitrogen in the plant's environment. This primarily takes place in older leaves which deteriorate from the tip towards the base of the leaf. Secondarily when the deficiency becomes severe new leaves and stem are much smaller in size than normal. This is because nitrogen is used in proteins and without enough nitrogen proteins cannot be made properly or in large enough amounts, so new leaves are smaller in stature. Also, old leaves are affected first because nitrogen is a nutrient that can be salvaged from old tissue and transported for use to new tissue. Not all nutrients can be removed once tissue has formed.



rpadgett37 said:


> Does it relate in any way to ammonia / ammonium?


Yes it does. Plants can use several different forms of nitrogen to grow. Ammonia/ium are both compounds which plants can absorb and use as a nitrogen source. In fact, plants take in all forms of nitrogen (Urea/nitrates/nitrites/ammonia/etc) and then convert them to NH3 (ammonia) inside the plant for use. So ammonia is technically the fastest way of getting nitrogen into a plant's system since it doesn't have to spend energy converting it to the form it uses. However, ammonia can also be toxic in fairly low concentrations to many species of plants and it is therefore not the most effective way to dose nitrogen (though some species do respond better to it than nitrate).



rpadgett37 said:


> How would one address a deficiency in this area?


You would add a source of nitrogen, usually potassium nitrate, though ammonia and urea can also technically be used as well (the last two are thought to cause algae blooms). You could also add root tabs or soil under your substrate. The cap prevents most of the nutrients from seeping out into the water column.



rpadgett37 said:


> A follow up question, once in the aquarium, outside of the nitrogen cycle, what is the relationship between these two?


The nitrogen cycle is NH3 → NO2 → NO3 each step done by a different species of bacteria. They are all usable forms of nitrogen to plants and are all absorbed to some degree. Other than that I don't know what relationship you are referring to.



rpadgett37 said:


> Can nitrate revert to ammonia / ammonium?


Nitrate can be converted back to ammonia/ium by bacteria, though this doesn't generally happen in our tanks because its not energetically favorable. Plants convert nitrate back to ammonia/ium inside their tissues before they bind it to amino acids for use in protein building, but this step costs energy (that plants get from sunlight). That is why most bacteria do not convert NO3 to NH3 - because it costs energy. They convert NH3 → NO2 → NO3 because each one of these steps gives off energy which bacteria can use as a food source.


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## rpadgett37 (Jan 2, 2014)

Thanks very much one and all. Crystal clear.

As to my question of nitrate reverting to ammonia, it came from something that happened in a friend's aquarium. She used too many root tabs with a high nitrogen content, then had an ammonia spike and associated by products (nitrite, nitrate). What I am guessing is that when something says nitrogen content without being specific, it can be ammonium and nitrate like SC Nitrogen.


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## Zapins (Jan 7, 2006)

rpadgett37 said:


> What I am guessing is that when something says nitrogen content without being specific, it can be ammonium and nitrate like SC Nitrogen.


Exactly right.


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## rpadgett37 (Jan 2, 2014)

I'm going to put this in my own words. Helps me clarify the concepts in my mind.

When plants begin to show a nitrogen deficiency, you have to look to the nitrogen cycle in the tank, meaning the ammonia going in the front end and nitrate coming out the back end.

Plants and BB consume ammonia / ammonium at the front. If I understand it correctly, plants will consume the majority while BB get a smaller amount. If the ammonia / ammonium concentration is low, plants may not be getting all of the ammonium / ammonia they require so they look to the back end for nitrate. Under these conditions, if nitrate concentrations are also low, plants may not be getting enough nitrate to make up for the low ammonium / ammonia concentrations at the front end. A nitrate deficiency is the result.

Seems like the solution can be addressed by increasing the ammonia concentration, the nitrate concentration, or both. On the front end, increasing the stocking level of the tank (other things I am sure) raises the ammonia / ammonia available to both plants and BB. Plants get more up front food. BB colonies grow to meet the new conditions in the tank ultimately leading to more nitrate produced at the back end. If front and back end nutrients rise enough, the plants will get everything they grow to grow and be healthy (with respect to ammonium / ammonia and nitrate).

Addressing just the nitrate issue, Potassium nitrate? I also know SC Nitrogen introduces both ammonium and nitrate. The goal would be to raise nitrate concentrations to at least 5ppm.

Is all of that on target?


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## Hoppy (Dec 24, 2005)

Unless you have quite a bit of experience with planted tanks, you should treat ammonia and urea as enemies, not as friends. Dose nitrates, preferably potassium nitrate, KNO3, and never add ammonia or urea to your tank. A pretty significant overdose of KNO3 isn't going to do any harm to either the fish or the plants, but the margin for error with ammonia and urea is much lower. Plants will do very well with just KNO3 as a source of nitrogen.


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## rpadgett37 (Jan 2, 2014)

Ok great. Thanks very much


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## Zapins (Jan 7, 2006)

rpadgett37 said:


> I'm going to put this in my own words. Helps me clarify the concepts in my mind.
> 
> When plants begin to show a nitrogen deficiency, you have to look to the nitrogen cycle in the tank, meaning the ammonia going in the front end and nitrate coming out the back end.


When plants develop a nitrogen deficiency it means there is no nitrogen in any available form in the water. So none of the 3 chemicals involved in the nitrogen cycle are in the water (NH3, NO2, NO3). In a fully established planted tank there is no true nitrogen cycle because the plants use up all the ammonia before bacteria have a chance to convert it all to nitrates. A very small amount is consumed by bacteria and converted but nowhere near as much as you'd have in a plantless tank.



rpadgett37 said:


> Plants and BB consume ammonia / ammonium at the front. If I understand it correctly, plants will consume the majority while BB get a smaller amount.


Yes.



rpadgett37 said:


> If the ammonia / ammonium concentration is low, plants may not be getting all of the ammonium / ammonia they require so they look to the back end for nitrate.


Yes, but not all plants prefer ammonia over nitrates. Some species (a lot of them infact) prefer nitrates over ammonia. But in general plants will use up the tiny quantity of ammonia in the tank quickly.



rpadgett37 said:


> Under these conditions, if nitrate concentrations are also low, plants may not be getting enough nitrate to make up for the low ammonium / ammonia concentrations at the front end. A nitrate deficiency is the result.


Yes. 

If there are no nitrogen sources (no urea, ammonia, nitrates, nitrites, etc) then plants develop nitrogen deficiencies. This is particularly common for aquatic plants since we grow them on inert substrates (quartz/fluorite/etc) rather than in soil which contains a lot of these nitrogen sources. Nitrogen is one of the macro nutrients and is used the most by plants with a close second being potassium. These two nutrients are frequently deficient in aquatic plants. Then iron is the next most common deficiency since it is not particularly stable in water and tends to precipitate out unless it is chelated and dosed frequently.



rpadgett37 said:


> Seems like the solution can be addressed by increasing the ammonia concentration, the nitrate concentration, or both. On the front end, increasing the stocking level of the tank (other things I am sure) raises the ammonia / ammonia available to both plants and BB. Plants get more up front food. BB colonies grow to meet the new conditions in the tank ultimately leading to more nitrate produced at the back end. If front and back end nutrients rise enough, the plants will get everything they grow to grow and be healthy (with respect to ammonium / ammonia and nitrate).


This is conceptually correct but as Hoppy pointed out there are other concerns with using urea and ammonia and nitrite. Urea breaks down into ammonia, and ammonia and nitrite tend to be quite toxic to plants and fish at fairly low concentrations and also seem to trigger algae growth. People have used them in their aquariums successfully but they are definitely not the standard source of nitrogen, at least not in the water column. They are ok to use in root tab form as long as they are sealed off from the water column. 

Also, plants will generally grow quite well using either front or back end nutrients (ammonia or nitrates) and do not grow that much better if offered both at the same time. Plants usually have a clear preference for one form or the other and will grow faster if given that form of nitrogen. Not all plants are the same, but I believe most aquatic plants do better with nitrogen supplied as nitrates rather than ammonia. This is supported by the fact that many plants will melt if ammonia concentrations rise above 2 ppm for an extended period of time (particularly HC, possibly crypts, etc).



rpadgett37 said:


> Addressing just the nitrate issue, Potassium nitrate? I also know SC Nitrogen introduces both ammonium and nitrate. The goal would be to raise nitrate concentrations to at least 5ppm.


Yes KNO3 for nitrates, these you'll want to keep between 10 and 25 ppm permanently. If you try to maintain 5 ppm you run the risk that your plants will have a good day and need 5+ ppm, and deplete the water column of all nitrogen, then they will not have enough nitrogen to keep growing and will either slow down their growth or cause deficiency symptoms if the duration is long enough.

You should keep the ammonia below 0.25 ppm, or safer at 0 ppm.



rpadgett37 said:


> Is all of that on target?


Pretty much!


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## Steve002 (Feb 7, 2014)

Definitely dose for nitrate not ammonia.


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## Diana (Jan 14, 2010)

Adding fish may or may not help. 

Adding fish food helps. 

Since most people increase the food when they add fish, it appears that it is the fish. 

Really, it is the nitrogen in the food (in the form of proteins) that shows up as ammonia, nitrite and nitrate as the fish, snails, shrimp and all the microorganisms work on it. 

If you had a tank with zero livestock, but kept adding fish food you would see the nitrogen cycle, and have nitrogen in the tank in all 3 forms. However, the plants and bacteria will keep on removing the ammonia and nitrite so all you would see in testing is the nitrates. Of course if you were not adding very much fish food, and had a lot of plants they would probably be using all the nitrogen you are adding.


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## rpadgett37 (Jan 2, 2014)

Interesting... the fish food I mean. And that makes total sense. Though I read about this in Diane Walstad's book (are you the same person?) about food as fertilizer, it didn't click with respect to Nitrogen in the water.

And use of KNO3 over SC Nitrogen makes sense as well. I'll be correcting this soon. It's probably posted somewhere in the forum, but for the sake of convenience, I'll ask here where I might be able to find KNO3?

And thanks one and all for your assistance here. This is a lot clearer in my mind now. I have this bookmarked and will refer back to it when needed.


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## zachawry (May 28, 2013)

So, if we think we might have a nitrogen deficiency, could this be solved by feeding the fish more? 

Thanks.


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## Diana (Jan 14, 2010)

I am not Diana Walstad. 
My background includes a lot of horticulture schooling and experience, which includes soils, fertilizer, chemistry and many related things.
You can add some nitrogen to the tank by feeding more. However, if the fish eat more they get fat, and can get sick and die from over eating. Also, the fish food needs to decompose before the N is available to the plants. I prefer to add N when I want to add N. KNO3 is the most common form for most planted tank people. 

KNO3 is available in several forms. It is an agricultural chemical, used as a fertilizer. In this form it is usually available in a 50 lb bag. This size is enough for a large club to share! 
It is also an ingredient in many stump removers, but be careful! There are stump removers that are different ingredients. 
It is also available on line, in reasonable quantities, from places like this:

http://www.aquariumfertilizer.com/


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## birbaliktanki (Jun 18, 2014)

Diana said:


> I am not Diana Walstad.
> My background includes a lot of horticulture schooling and experience, which includes soils, fertilizer, chemistry and many related things.


i thought so too. but am afraid to ask. :smile:


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## Zapins (Jan 7, 2006)

I agree with Diana. Adding fish food for nitrates can be done but it is not as desirable a method of adding nitrogen to a tank as KNO3. Especially in a higher light, CO2 injected tank. This is because it adds other chemicals as well as the nitrogen, including organic material which can promote algae and debris buildup.

Also Diana Walstad's screen name is dwalstad on the forums.


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