# Evidence of AQUARIUM plants preference of ammonium over NO3??



## overdoser

I've exhausted my search to see if any research has been done regarding this matter on any desirable plants of the hobby. The only test results I came across were from 'aquabotanic' website, of which the author adamantly proclaimed "aquatic plants prefer ammonia over nitrate as their nitrogen source." 
However, these 'plants' used in the test that showed preference to ammonium were various strains of moss and duckweeds- commonly found in ditches, don't root into substrate, thrive in poor water- not exactly desirable or of any use to most aquarists.
Does anyone have any research they'd like to share?

I'll share my latest dosing experiment with my heavily planted 90gal tank: 
For over a year I had supplemented N via KNO3 (dry mix) and maintained a level (according to my cheap tester) of approx. 10ppm with excellent plant growth and algae at near unnoticeable levels. A few months ago, I ceased the KN03 dosing and bio filtration to see if my large fish load(healthy and robust) could possibly meet the demands of the plants. It didn't, and my plants pooped out shortly after. My nitrate level tested at 0ppm. Fish still great.
This time, I decided to try seachem's nitrogen supplement- since it's label says it contains "plant preferred" ammonium along with nitrate. After a couple weeks of the recommended dosing, my plants showed no signs of recovery but hair, bba were coming on strong. My nitrate level still was only testing at 0ppm. So, I thought the dose may be insufficient for my setup and decided to increase the next dose to twice the recommended. Half of my robust cardinal tetras died within minutes, thus ending my experiment with this product. Coincidence?????? My tap ph is slightly on the high side and I understand ammonia is more toxic in this situation but irregardless, my patience was spent on waiting for my plants to respond. 
I resorted back to my dosing good ol' KNO3 powder, and after a week my plants were pushing out new growth and the algae was disappearing. NO3 measured approx. 5ppm.
I like to try experiments, but for me adding ammonium to the tank is off the list. Can someone explain to me how "free ammonia is not released and unavailable until used by the plants" with this product? I realize my starved plants can lead to algae's success, but I also realize the plant guru has induced algae blooms by artificially adding small amounts of ammonium in his experiments. 
In my ignorant opinion, it's not worth the risk. Or the $7.99.


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## Freemann

I am preparing a text on this one. I possitivelly have seen incredible change on my plants growth and all since I started adding ammonium throu Urea in addition to KNO3 the difference in growth, health (even species that were not growing before started growing). This thing has really altered the health in my tanks of course all the rest were added properly as before. This experiment of mine is going on for at least 4 months, I had no deaths from adding urea (1 ppm ammonium from it daily), on the contrary I had 100's new cherry's and lots of new baby glowlights in the tank, but I do have a big biofilter in the tank and the tank is a jungle at the moment. A friend with lots of experience that is conducting the same experiment in parallel with me had similar results as well. I will very soon post more on this.
Still ammonia is something to be cautious with.
For the time have a look on this one (you can ignore the rest, just this guys post and specially the link that is included):
http://www.barrreport.com/general-plant-topics/3506-alternathera-reinekii-problem.html#post20196


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## orlando

This is great stuff, keep it coming.


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## AaronT

I think the problem may have been eliminating the biofiltration. I suspect as Freeman has experienced, that had the filter been left on the death of the cardinals might have been avoided. 

Was there anything creating flow in the tank when you were dosing the Seachem nitrogen? That's a huge variable that you also changed. Good flow is crucial to healthy plant growth.


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## overdoser

Freemann said:


> I am preparing a text on this one. I possitivelly have seen incredible change on my plants growth and all since I started adding ammonium throu Urea in addition to KNO3 the difference in growth, health (even species that were not growing before started growing). This thing has really altered the health in my tanks of course all the rest were added properly as before. This experiment of mine is going on for at least 4 months, I had no deaths from adding urea (1 ppm ammonium from it daily), on the contrary I had 100's new cherry's and lots of new baby glowlights in the tank, but I do have a big biofilter in the tank and the tank is a jungle at the moment. A friend with lots of experience that is conducting the same experiment in parallel with me had similar results as well. I will very soon post more on this.
> Still ammonia is something to be cautious with.
> For the time have a look on this one (you can ignore the rest, just this guys post and specially the link that is included):
> http://www.barrreport.com/general-plant-topics/3506-alternathera-reinekii-problem.html#post20196


Terriffic- I look forward to your full report! I too wanted to experiment with urea, but I succumbed to the red flags waved about trying it and due to the fact I jumped on the opportunity to obtain several species of next to impossible to get fish in my neck of the woods (not the cardinals) and didn't want to risk their health on my plant experiments.

If it's possible, please share your other nutrient dosing/ parameters that you use in conjunction with the ammonium that produced success. Lay it on us, man. All the gorey details.
Thanks for the link- I've recently discovered some interesting information on calcium presence and how it affects/ hinders some plants' ability to assimilate nitrate. I am curious to know if this is true with all aquatic plants or if some species make adjustments more readily to accommidate certain conditions. I am plagued (or blessed?) with hard tap water and have dappled in the past with softening it but now I am learning there's a just a tad (actually a heap) of science a person should become aware of regarding this issue if limited to just one aquarium in operation; i.e. I need to set up 3 or 4 experiment tanks.

On a side note, I do not think my fish's demise was a result of the nitrogen supplement I was dosing. I'm sure it most likely was due to the poor health of my vegetation from a lack of certain nutrients/ imbalance. I just thought I'd share my experience in case there's anyone less educated than myself on nitrogen dosing. Simply following general guidelines (a lot of them out there) just won't always produce results in every unique tank of water.


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## overdoser

AaronT said:


> I think the problem may have been eliminating the biofiltration. I suspect as Freeman has experienced, that had the filter been left on the death of the cardinals might have been avoided.
> 
> Was there anything creating flow in the tank when you were dosing the Seachem nitrogen? That's a huge variable that you also changed. Good flow is crucial to healthy plant growth.


I guess I should have left out the bit about my fish dying. It was a secondary point- my main objective was to share my plants' lack of success with dosing this source of N. I have recently gained some insight on factors that can limit plants uptake of N, obviously contributing to poor health, which in turn most likely produced an unfavorable condition for those fish. However, I would just like to know how the ammonia is "complexed" in this solution and unavailable until "utilized" by the plants. The source of this ammonium is urea. Is this a similar situation as to iron being chelated?

As far as my tank status (4' long): I run a strong powerhead, which I use for co2 injection, that outlets on one end of the tank bottom and gushes the entire length to the opposite end. On this opposite end, at the top of the water column I use an AC 70 that outflows to the front of the tank and downward, creating a very nice mix. (This seems to do a fabulous job of churning co2 gas and my fish love having a 4' long riverine gush to swim against). 
I simply just removed the bio substrate from the AC filter when I wanted to try my experiment with ammonia provided by the large fish load (all filters still running). This was nothing new, as for over a year I have gone without any "bio media" in my filters and the plants provided an ammonia free environment with vigorous fish health. This latest removal of the bio filter was an attempt to cease nitrate production to find out if soley the available ammonia would satisfy my plants. (I only add bio media to provide another nitrate source for plant food). Furthermore, using biomedia in conjunction with this seachem product would seem to contradict it's purpose. Again this latest test carried on for a month, with the fish in great condition. It was just a shocker that day I used the double dose and I lost those fish. 
There's a possibility they just got a concentrated blast of the liquid before it got dilluted:boxing:
I don't know enough about the science behind this product to blame it.
I appreciate your insight though.


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## AaronT

I honestly don't know the mechanism behind the ammonium being only available to the plants. My current method of fertilization is to use mineralized topsoil. What this means is that the soil has been soaked and dried several times in order to help the bacteria within break down any organic solids and convert them to NH4. I add a little crushed limestone in the bottom of the tank to buffer the soil from becoming too acidic, some potash for an initial postassium source and some clay to bind the soil and provide iron. 

The idea behind it is that the plants will uptake the NH4 from the soil and use that as the main source of macronutrition. So far it works quite well with no dosing I am able to grow 90% of the plants out there. There are a few that just seem to need some nutrients in the water column. 

Of course, adding NH4 to the water column is a whole different ball game. I'm interested to see Freeman's write-up. I always wanted to experiment with NH4 dosing, but never had the tank without fish to try it in.

Thanks for sharing your experienes overdoser.


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## BryceM

Well, I've never tried NH4, so I might not have that much to add here, but there are a couple of chemistry points to keep in mind.

Everyone should realize that when added to water, there is essentially no difference between adding NH4+(ammonium) or NH3 (ammonia). Ammonium is freely and *rapidly* converted to ammonia by reacting with water and visa-versa. The ratio of ammonia to ammonium depends greatly on the pH. In typical soft-water tanks (pH <7) there is actually very little free ammonia. In hard-water tanks (ph > 8 ) ammonia levels can become toxic to fish much quicker.

The thought of deliberately adding ammonia to an aquarium with fish in it doesn't sit well with me, regardless of what the plants would like.

Also, these two compounds do not simply dissolve in water but act as an acid & base in their own right. Pure ammonia acts as a base (it strips a hydrogen from water, leaving hydroxide (HO-). A large enough quantity will raise the pH rather suddenly (think windex), but by then it would have killed the fish anyway. An ammonium compound will act as a weak acid, donating a proton to water to form H3O+. Adding this will cause a pH drop.

It is, of course, all dose related. A constant low-level infusion of ammonia (or ammonium) will probably supply the needs of the plants very nicely while not being toxic enough to bother the fish.

Urea is certainly an excellent source of nitrogen, but chemically it is not freely interchangable with ammonium. By itself, it is much less toxic than ammonia (or ammonium). Land animals actually expend considerable quantities of energy to convert ammonia to urea. It dissolves freely in water and can be converted back to ammonia (or ammonium) but this process is depends on urease (an organic enzyme), and is actually rather slow, taking hours or days. It's also not clear to me if aquarium plants require ammonium for uptake, or if they uptake the urea directly and then convert it to various organic nitrogen compounds internally.

I'm interested to see what Kekon finds. Personally, I think there are two options that make sense. The first is to supply ammonium in the substrate and the second is to supply nitrate in the water column. Ammonium-rich substrates seem to work well (ADA, Aaron's method) as long as the ammonium stays where it belongs and doesn't get in the water column. The other method that makes sense is NO3- addition. Nitrate isn't terribly toxic in reasonable concentrations, plants seem to use it just fine, and it seems to be less "touchy" than trying to dose an ammonia to the water column.

A nitrogen-rich substrate is used by lots of people (think El Naturale), but all of these substrates eventually become depleted. For an aquascape with a lifespan of a few months (think ADA, AGA, or any other photo contest), this is no big deal. For a long-term setup, especially in an intensely-driven growth environment (high-light, high-CO2, fast growers) water column dosing of NO3 might make more sense.


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## Freemann

Well as I said I have been dosing Urea for 4 months now you can see some of the results in this photo:
http://www.aquaticplantcentral.com/...=5143&original=1&c=searchresults&searchid=987
By now I understand that this is the reason of the high success with all the rich substrates I have been using myself for all this years, but avoiding this substrate change thing every few years is a major advantage of urea in the column addition. I could monitor ammonia in the column with the colorimeter but frankly I am too busy this days, still I have seen absolutely no sign of stress to any fish or invert, none. For me there is no comparison between KNO3 suplementation and urea addition (this is an approximation, I have added a calculation for ammonia in urea in chuck's old web based calculator if anyone is interested, it needs double checking) NO3 is not getting assimilated the way this stuff does when I add this stuff plants go mad, when I add NO3 they don't and when I add a lot of KNO3 they freak out, this is far superior to NO3 for me there is no comparison, I can only assume that it may have to do with Ca assimilation maybe somehow Ca is not assimilated and then NO3 is not assimilated, also the path alway goes from NO3 to ammonia before it can be used in the plants so what a better than giving it directly to them so the intermediate stages are avoided, this is clearly demonstrated in the forties article on beans on my link above. But this is only an assumption as I said. Ammonia can be a major problem if all the rest of the ferts are not added in abundance and the plant mass is not satisfactory, so you new to the ferts and all don't start adding it like it is a harmless stuff, but you experienced guys I would really like to compare results on this one. By the way all the yellowing I have been seeing in my plants for years were never iron deficiency they were there with 10 ppm NO3 and 40 ppm and 60 ppm but they were gone with just a tiny 1 ppm ammonia a day completely that was the best part. Umbrosum 5 times was added in the tank it died, it now grows like crazy, mayaca white leaves withering grows like crazy, didiplis superb growth I hack it and it regrows like mad, townoi tons, 2 species stellata, aromatica in total 48 species grow in 400 lt of water at the moment only things that still curl are the nasaeas but they do not die, they just grow like old distorted trees, I am still working on them.


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## BryceM

Hmmm. I'm not opposed to trying it. It's possible that some plants do just fine with water column NO3 while others need something "easier to digest" like direct urea or NH4+. Theoretically the conversion from urea to ammonium should only occur where urease is found - in bacteria in the substrate and in the plants themselves. If this is true it would be fairly safe for the fish and shouldn't incite too much of an algae issue.

....... but I'm not that displeased with what I'm doing now. I'm using only KNO3 as a nitrogen source and things are doing reasonably well. Maybe I'll try it in my smaller tank. It certainly is dirt cheap. Exactly how much are you using day / per week?


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## Freemann

Well I tell you it depends after a major trim I go cautiously and add 1/32 (0,2 gr) of the spoon per day (around the 8th hour of the light timer circle) but when the tank is in full jungle mode 1/16 (0,4 or even 0,6 gr) can go in np that is in 408 lt water column under 450 MH 11 hours per day the urea comes in granules 2 mm wide. I also add lots of iron (I added this before aswell).


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## overdoser

Freemann said:


> Well as I said I have been dosing Urea for 4 months now you can see some of the results in this photo:
> http://www.aquaticplantcentral.com/...=5143&original=1&c=searchresults&searchid=987
> By now I understand that this is the reason of the high success with all the rich substrates I have been using myself for all this years, but avoiding this substrate change thing every few years is a major advantage of urea in the column addition. I could monitor ammonia in the column with the colorimeter but frankly I am too busy this days, still I have seen absolutely no sign of stress to any fish or invert, none. For me there is no comparison between KNO3 suplementation and urea addition (this is an approximation, I have added a calculation for ammonia in urea in chuck's old web based calculator if anyone is interested, it needs double checking) NO3 is not getting assimilated the way this stuff does when I add this stuff plants go mad, when I add NO3 they don't and when I add a lot of KNO3 they freak out, this is far superior to NO3 for me there is no comparison, I can only assume that it may have to do with Ca assimilation maybe somehow Ca is not assimilated and then NO3 is not assimilated, also the path alway goes from NO3 to ammonia before it can be used in the plants so what a better than giving it directly to them so the intermediate stages are avoided, this is clearly demonstrated in the forties article on beans on my link above. But this is only an assumption as I said. Ammonia can be a major problem if all the rest of the ferts are not added in abundance and the plant mass is not satisfactory, so you new to the ferts and all don't start adding it like it is a harmless stuff, but you experienced guys I would really like to compare results on this one. By the way all the yellowing I have been seeing in my plants for years were never iron deficiency they were there with 10 ppm NO3 and 40 ppm and 60 ppm but they were gone with just a tiny 1 ppm ammonia a day completely that was the best part. Umbrosum 5 times was added in the tank it died, it now grows like crazy, mayaca white leaves withering grows like crazy, didiplis superb growth I hack it and it regrows like mad, townoi tons, 2 species stellata, aromatica in total 48 species grow in 400 lt of water at the moment only things that still curl are the nasaeas but they do not die, they just grow like old distorted trees, I am still working on them.


Wow. 
Just so I am fully clear on this- When you were dosing with KNO3 you were also using an enriched substrate. With your current ammonia dosing do you have an enriched substrate or do you believe it just isn't necessary anymore with this luxuriant growth you've achieved?
Also can I ask if your substrate was enriched during the failed attempts with umbrosum? My past attempts with it have melted irregardless of nitrate level or substrate. Amazing.

I will try to find the article I read recently on calcium's alleged critical role with nitrate assimilation. My description of it will be vague- but during the process of breaking down nitrate, acids are produced in the plant, and without the presence of ca there are negative impacts, or the plant shuts down and simply won't use the nitrate.
This is why now I'd like to have 3 or 4 tanks to run experiments with nitrate, ammonia, and calcium being the variables.

Thanks again for sharing this, sir. You definately answered my question about 'desirable' plants consuming ammonia from the success list you provided.


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## overdoser

I've often wondered: If KNO3 'works just fine' for growing my plants, who cares if ammonia is the preferred form, and besides it could kill my fish.

Well KNO3 just doesn't always work, and if you don't know the parameters that prevent it from nourishing your plants, it can be a frustrating ordeal. If ammonia, as the source of N, requires fewer parameters that need to be met and maintained for the plants' uptake, then it sounds like a very worthwhile option for the hobbyist.(risks considered)

So for you chemically-inclined, I ask: Is there a way to determine the amount of ammonia needed in a volume of water such that it satisfies plants but doesn't approach the toxicity level to fish? What is the toxicity level in general to tropical fish and how does ph affect it? If this can be quantified, a person could concoct a dosing solution similar to a KNO3 mix, correct?


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## helgymatt

This is no suprise that some plants will grow better in the presence of ammonium rather than nitrate. Many land plants prefer one over the other and this has been documented in dozens of horticultural publications. I'm sure there are some out there about plants that prefer ammonia/ammonium in hydroponic situations. That would be very applicable to aquarium situations. 

Here's some interesting research about growing wheat hyrdoponically with varying rations of NH4+/NO3-http://www.usu.edu/cpl/research_hydroponics.htm. Ammonium was not beneficial in this case. I'll be sure to look into this more and provide more feedback. This topic is especially interesting to me because some my research as a grad student in hort has to do with nitrate/ammonium issues.


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## AaronT

guaiac_boy said:


> Everyone should realize that when added to water, there is essentially no difference between adding NH4+(ammonium) or NH3 (ammonia). Ammonium is freely and *rapidly* converted to ammonia by reacting with water and visa-versa. The ratio of ammonia to ammonium depends greatly on the pH. In typical soft-water tanks (pH <7) there is actually very little free ammonia. In hard-water tanks (ph > 8 ) ammonia levels can become toxic to fish much quicker.


Ah, so that must be why Aquasoil is designed to initially drop the pH and keep it lower over time.


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## Freemann

> Also can I ask if your substrate was enriched during the failed attempts with umbrosum? My past attempts with it have melted irregardless of nitrate level or substrate.


This tank was always flourite with 1 cm agricultural peat on the bottom (which by now has gone for sure), no the umbrosum would simply not grow. This was always intended to be a poor substrate tank (I consider flourite to be this). When I talked of rich substrate tanks I refered to the tanks with forest soil under the gravel that I kept for the past 28 years.


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## kekon

I tried different sources of N in my tank:

- NH4NO3
- CO(NH2)2 (urea)
- NH4(OH)
- NH4HCO3

From my experience i know we should not keep 0 ppm NO3 in our tanks even though plants are growing well by uptaking N from NH4 only or urea. There should be some NO3 in the tank because 0 ppm NO3 always cause GDA algae in my tank. I never had any issues with algae by adding NH4 (0.5 ppm NH4 daily) Algae appear in my tank when NO3 and PO4 is too low or when PO4 is high and NO3 is barely detectable. As far as i know Seachem Nitrogen contains N in a form of KNO3 and guanidine. I've never used guanidine but i think it's more "agressive" form of N than ordinary urea and it may have caused fish death in overdoser's tank. 
I added urea into my tank without problems, about 0.5 ppm daily. Such a high dose caused NO3 rising - urea was quickly converted to NO3; a few hours after adding urea i was able to see higher NO3 (it usually rose from 2..3 ppm to over 5 ppm). A person i know doses only urea as N source and he obtains very good results (especially HC grows like crazy). You can see it here:

http://images31.fotosik.pl/141/ff988f075e3ebbdbmed.jpg
http://images24.fotosik.pl/158/b0049b0785606d0a.jpg
http://images24.fotosik.pl/158/9ca1d9eb3199558a.jpg

He also uses very soft water (GH = 3) and undetectable PO4 (in very soft water it is possible to grow plant at low PO4 and NO4). By adding urea NO3 is kept at about 5 ppm in his tank. He adds about 0.227 ppm of urea daily. When he added 0.4 ppm some plant tips were stunted (too much N).

The most dangerous chemical compound i used was NH4(OH). It is strong, stinking and corrosive base liquid. Once i made a mistake in my calculations and insead of adding 0.1 ppm NH4 i added 0.8 ppm daily. It ended up with killing 10 fish. Some plant tips were stunted within one day but some plants grew an inch a day ! NH4(OH) is extremely toxic to fish and i no longer use it.

I found quite good source of adding N. There is N fertilizer produced by "Drak" company called "Eudrakon N". This fertilizer is designed to use in planted tanks. It is made of urea + KNO3 + NH4NO3. Maximum recommended daily dose is (1 ml / 50L):

1 ppm NO3
0.1 ppm NH4
0.33 ppm urea

These amounts are entirely safe to plants and fish. The main advantage of adding 3 forms of N simultaneously is that we can mantain lower NO3 in the tank and obtain the same good growth which can be achieved by adding only NO3 in higer amounts. However it seems than such salts as KNO3 or Ca(NO3)2 are still very good N sources and if someone uses them with good results there is no need to switch to NH4 or urea. One must also take into account the fact that NH4 can burn plant tips much severely than NO3 (it resembles Ca deficiency).


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## evergreen

kekon said:


> A person i know doses only urea as N source and he obtains very good results (especially HC grows like crazy).


What kind of substrate was there? And were there any additives which could be as nitrogen source?


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## kekon

As far as i know he uses plain gravel without any additions. However, if he adds too much urea (about 80% more) some plants have stunted tips (too much nitrogen in soft water).


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## evergreen

kekon said:


> As far as i know he uses plain gravel without any additions. However, if he adds too much urea (about 80% more) some plants have stunted tips (too much nitrogen in soft water).


When speaking about nitrogen uptake we should always mention the amount of CO2 and photoperiod + light intensity. I'm dosing PPS-PRO and I always have some plant species stunted if there will be 30 ppm of CO2 and just 1 ppm of NO3 (one dose of PPS-PRO). And all is perfect if CO2=10-15 ppm. The same situation is with light. So what is CO2 level and photoperiod in tank which you are talking about? The plant condition on the pictures is excellent that's why I ask you about that.


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## kekon

As far as i know the photoperiod is set to 10h and CO2 is about 20 ppm. These are typical values. He doesn't dose any PO4; he maintains there is enough PO4 from fish food (mainly from blood worms). I don't like 0 ppm PO4 personally but in his case it works well.


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## evergreen

kekon said:


> the photoperiod is set to 10h and CO2 is about 20 ppm.


These are the key words I wanted to hear. Thank you, kekon...........


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## Error

kekon said:


> I found quite good source of adding N. There is N fertilizer produced by "Drak" company called "Eudrakon N". This fertilizer is designed to use in planted tanks. It is made of urea + KNO3 + NH4NO3. Maximum recommended daily dose is (1 ml / 50L):
> 
> 1 ppm NO3
> 0.1 ppm NH4
> 0.33 ppm urea


Where do you get this stuff? I'd like to try it.


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## Riba

Error said:


> Where do you get this stuff? I'd like to try it.


Just found it at http://www.drak.de/shop/eudrakon-bottle-p-118.html


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## kekon

> Where do you get this stuff? I'd like to try it.


I have plenty of urea, KNO3 and NH4NO3 so i make the fertilizer myself. The recipe for 1 liter is:

- 53.3g KNO3
- 22.2g NH4NO3
- 16.6g CO(NH2)2 (urea)

Dosing: max. 1ml/50 liters daily


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## Error

kekon said:


> I have plenty of urea, KNO3 and NH4NO3 so i make the fertilizer myself. The recipe for 1 liter is:
> 
> - 53.3g KNO3
> - 22.2g NH4NO3
> - 16.6g CO(NH2)2 (urea)
> 
> Dosing: max. 1ml/50 liters daily


Where might someone procure ammonium and urea? I used to get my stuff from Greg Watson.


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## kekon

You can try to find any agricultural store, they usually sell urea and NH4NO3, but NH4NO3 is often sold with addition of CaCO3 which makes the whole mixture less prone to explosion (NH4NO3 is a strong oxidizng agent) so if they have NH4NO3 one must make sure it's without CaCO3.


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## Error

kekon said:


> You can try to find any agricultural store, they usually sell urea and NH4NO3, but NH4NO3 is often sold with addition of CaCO3 which makes the whole mixture less prone to explosion (NH4NO3 is a strong oxidizng agent) so if they have NH4NO3 one must make sure it's without CaCO3.


Thanks! I'll check it out this weekend. Does your friend dose this stuff daily, or does he alternate? When/how often does he dose his traces? What about water changes?


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## kekon

He doses urea daily, but without NH4NO3 and KNO3. The recipe i posted above is used by me with good results but he adds urea only. He adds traces after water change and on daily basis. However, i don't know what micro ferts he uses and what doses; the only thing i know is that the fert added after water change (once a week) is one of those ferts used for hydroponic purposes. NO3 is about 5 ppm, GH = 3, K = 50 ppm (he adds so much potassium to changed water every week)


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## Sumo

When you start a tank, you can use the 3 forms of N or must start only with NO3? 
Sorry for my English


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## kekon

When setting up a tank it is not wise to add any nitrogen as it will be produced in high amounts before the tank stabilizes. During this period, many different form of nitrogen will be produced including NH3/NH4, NO2, NO3 and some urea when you introduce some fish.


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## Sumo

Thank you, I understand, but I mean when you need N. I always take the plants as a reference, but always I used KNO3. My specific question is referring to when it is necessary to add N. I hope to be understood as translators use of the site, both to read and to write.
Regards.


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## kekon

> Thank you, I understand, but I mean when you need N


Sorry, it was my mistake...
If you notice your plants are yellow on old leaves and growth is slow it a sign you have to add N.
In low GH water (3..6) it is enough to add 0,5..0,7 ppm NO3 daily. In harder water (above 6) one can add 1 ppm NO3 daily. You don't need necessary to add urea or NH4. I think that at the beginning adding only NO3 is fine.


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## Sumo

Thanks Kekon. 
This is what I thought. 
In my country, Uruguay, we have soft water, and we have followed in our forum, Kekon post on the subject. 
http://www.bouzada.d2g.com/foro/phpbb2/viewtopic.php?t=902
In my next aquarium I want to use the 3 forms of nitrogen. 
Thank you for sharing your experiments


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