# With what replace KNO3 ?



## eminor (22 Jul 2022)

Hello, i've read that it's easier for plant to to take nitrogen from urea than NO3, what is the chemical name for urea, there is NH4NO3 but can't buy it in my country, what is the alternative, NH₄HCO₃ ? thx


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## KirstyF (22 Jul 2022)

I think it’s Urea CO(NH2)2 and NH4NO3 is ammonium nitrate but I could be wrong so hoping one of our ‘chemists’ can verify.😊


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## Zeus. (22 Jul 2022)

KirstyF said:


> I think it’s Urea CO(NH2)2 and NH4NO3 is ammonium nitrate


Correct on both


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## jolt100 (22 Jul 2022)

Also known as Ureum in Europe?


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## eminor (22 Jul 2022)

thx guys, is it risky to divide the nitrogen 50/50 NO3/urea ? urea seems to be a nuclear power plant


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## John q (22 Jul 2022)

eminor said:


> Hello, i've read that it's easier for plant to to take nitrogen from urea than NO3,


Yes plants use less energy converting ammonia/m.. 
Be warned... algae also prefer ammonium  to kno3.
Personally I've tried urea and didn't notice any difference. Healthy plants will eat what they can, folks with unhealthy plants will chase their tails and look for easy alternatives. Sorry to be blunt but the easy way doesn't exist. 👍


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## plantnoobdude (22 Jul 2022)

eminor said:


> thx guys, is it risky to divide the nitrogen 50/50 NO3/urea ? urea seems to be a nuclear power plant


As long as ph is Low and you are doin small doses it is safe.
I would dose anywhere from 1-3ppm Nitrogen from urea/ 4-13ppm no3. Split into daily dose.


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## John q (22 Jul 2022)

plantnoobdude said:


> I would dose anywhere from 1-3ppm Nitrogen from urea


So would I, providing you've no critters in the tank.


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## eminor (22 Jul 2022)

John q said:


> Yes plants use less energy converting ammonia/m..
> Be warned... algae also prefer ammonium  to kno3.
> Personally I've tried urea and didn't notice any difference. Healthy plants will eat what they can, folks with unhealthy plants will chase their tails and look for easy alternatives. Sorry to be blunt but the easy way doesn't exist. 👍


Well, my plant are in a good shape, just want to boost green's 


plantnoobdude said:


> As long as ph is Low and you are doin small doses it is safe.
> I would dose anywhere from 1-3ppm Nitrogen from urea/ 4-13ppm no3. Split into daily dose.


my tap is 7 ph, with co2 (24/7), ph 6 so it's fine i think
*
By the way, last question, i promise, what form of nitrates does tap water contain ? thx*


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## plantnoobdude (22 Jul 2022)

eminor said:


> Well, my plant are in a good shape, just want to boost green's
> 
> my tap is 7 ph, with co2 (24/7), ph 6 so it's fine i think
> 
> *By the way, last question, i promise, what form of nitrates does tap water contain ? thx*


Ph sounds good. Start with a small dose and fish should be fine.
Tap water should be mostly no3, and traces of nh4/nh3 and no2.


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## John q (22 Jul 2022)

eminor said:


> By the way, last question, i promise, what form of nitrates does tap water contain ?


One atom of nitrogen and 3 atoms of oxygen 😀


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## JoshP12 (23 Jul 2022)

eminor said:


> Hello, i've read that it's easier for plant to to take nitrogen from urea than NO3,


plants have pathways to use NO3 and NH3/4 … in a perfect world, you deliver the “perfect” proportion (for other current, fixed conditions) to suit the plants need. 

But the world is not perfect, so the plant can convert an imbalance of NO3 to NH3/4 and vice versa … cool. 

A somewhat analogy: 

So the plant want to have a cake base and the icing from the store so it can just make a cake … but if you give it flour and eggs etc, it can make the icing and cake base … but it requires some “work”. 

Urea on the other hand is “used” by the plant via an enzyme urease and that enzyme yields co2  and the nitrogen source by splitting the urea. So what you have is this “trick” to get co2 into your plant without worrying about flow!!!!! …

 who cares about gas laws when a fish can just pee on a nearby plant and fertilize it with N and CO2! 

So is it easier? I mean, you get co2 for “free” … does the plant have an easier time? It gets co2 for “free”. 

If you feed only NO3, you need to convert some and that costs co2. If you feed only ammonia, it needs to convert some and that cost co2. Urea gives N and co2 … liquid gold. 

But I mean … what if your flow and distribution is on point such that co2 is already being delivered appropriately …  then why bother with urea. Just add another fish and feed more. 

This is where @John q can almost say with confidence his co2 and flow were on point when he dosed that urea … since the “change” made no noticeable difference.


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## Hufsa (23 Jul 2022)

JoshP12 said:


> who cares about gas laws when a fish can just pee on a nearby plant and fertilize it with N and CO2!
> 
> But I mean … what if your flow and distribution is on point such that co2 is already being delivered appropriately …  then why bother with urea. Just add another fish and feed more.


I might be misremembering, but I thought the fish species we keep in our tanks produce only ammonia, and that the group of fish that produce urea are not the kind we would keep in a fish tank?
If this is the case then adding more fish doesnt necessarily do exactly the same thing?


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## JoshP12 (23 Jul 2022)

Hufsa said:


> I might be misremembering, but I thought the fish species we keep in our tanks produce only ammonia, and that the group of fish that produce urea are not the kind we would keep in a fish tank?
> If this is the case then adding more fish doesnt necessarily do exactly the same thing?


Guilty as charged …

Found this paper: Urea excretion as a strategy for survival in a fish living in a very alkaline environment - PubMed

Turns out they produce primarily ammonia with “some” urea … go figure.

Still nice however especially if we are dosing some NO3.


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## Hanuman (23 Jul 2022)

eminor said:


> Well, my plant are in a good shape, just want to boost green's


Add more NO3 and be done with it instead. Simple, easy, safe and no need to be daily dosing and being careful etc etc.


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## John q (23 Jul 2022)

Hufsa said:


> I might be misremembering, but I thought the fish species we keep in our tanks produce only ammonia



Its amazing how many studies have been done regards Amonnia & Urea transporters in fish.
In the main I'd tend to agree with you that Amonnia will account for the bulk of gill or poop excretion by fish but suspect there will be some urea produced, albeit in small quantities. 

If anybody hasn't got plans to stick pins in their eyes this afternoon I found this article rather interesting, it's basically a review of years of studies into this question. 









						Ammonia and urea transporters in gills of fish and aquatic crustaceans
					

SUMMARY. The diversity of mechanisms of ammonia and urea excretion by the gills and other epithelia of aquatic organisms, especially fish and crustaceans, has been studied for decades. Although the decades-old dogma of `aquatic species excrete ammonia' still explains nitrogenous waste excretion...




					journals.biologists.com


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## JoshP12 (23 Jul 2022)

It really is this rabbit hole where we realize the crux of the EI ideology.

Frankly, go look at Tom Barr’s photos and journals etc and videos of when he feeds. There is one where he lobs handfuls and handfuls of food into a tank that is “overstocked” by many.

Then he lards in KNO3 (at the time). 

Using this thread only, you can immediately see why that works and I reckon if he did not do that, there is a chance he would either have to turn up co2, adjust flow, adjust O2, adjust agitation, or simply have leggier plants.


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## _Maq_ (23 Jul 2022)

JoshP12 said:


> the plant can convert an imbalance of NO3 to NH3/4 and vice versa … cool


Not sure whether I've understood the context but plants cannot convert ammonium into nitrate.
In general, I've studied more than just a few papers on the question of nitrate vs. ammonium nutrition of plants, esp. submerged plants. In sum, it is believed that aquatic plants slightly prefer ammonium, yet in most instances, plants grew best when both ammonium and nitrates were available.
The issue is not that simple just to say 'assimilating ammonium is less demanding energetically'. There are circumstances which must be included into account.


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## eminor (23 Jul 2022)

JoshP12 said:


> plants have pathways to use NO3 and NH3/4 … in a perfect world, you deliver the “perfect” proportion (for other current, fixed conditions) to suit the plants need.
> 
> But the world is not perfect, so the plant can convert an imbalance of NO3 to NH3/4 and vice versa … cool.
> 
> ...


Damn, i have no fish in that tank, i really need urea, to get more room for error with flow =)

does prilled urea the same as powder ? it say 46% urea


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## dw1305 (23 Jul 2022)

Hi all, 


eminor said:


> does prilled urea the same as powder ? it say 46% urea


You need to be a little bit careful, because cheaper urea prills often <"have biuret present">.

cheers Darrel


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## eminor (23 Jul 2022)

dw1305 said:


> Hi all,
> 
> You need to be a little bit careful, because cheaper urea prills often <"have biuret present">.
> 
> cheers Darrel


Thanks, does 46% urea mean that i need to double the amount of the ifc calculator ?


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## dw1305 (23 Jul 2022)

Hi all,


eminor said:


> Thanks, does 46% urea mean that i need to double the amount of the ifc calculator ?


That, 46%, is the <"nitrogen (N) content of urea (CO(NH2)2)">, so I'm guessing the prill is actually 100% urea?

The 46% comes from the <"proportion of nitrogen in urea">.

cheers Darrel


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## Hanuman (23 Jul 2022)

eminor said:


> Thanks, does 46% urea mean that i need to double the amount of the ifc calculator ?


In the IFC Calculator:


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## John q (23 Jul 2022)

_Maq_ said:


> plants cannot convert ammonium into nitrate


Seriously


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## eminor (23 Jul 2022)

dw1305 said:


> Hi all,
> 
> That, 46%, is the <"nitrogen (N) content of urea (CO(NH2)2)">, so I'm guessing the prill is actually 100% urea?
> 
> ...


here is what they say about it 



> Urea Technical with 46% nitrogen is used as a nitrogen fertilizer especially on summer crops. In the form of homogeneous pearls and associated with an anti-motant, Urea has the advantage of being spread in a regular way.


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## _Maq_ (23 Jul 2022)

John q said:


> Seriously





Taken from Marschner.


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## JoshP12 (23 Jul 2022)

_Maq_ said:


> Not sure whether I've understood the context but plants cannot convert ammonium into nitrate.
> In general, I've studied more than just a few papers on the question of nitrate vs. ammonium nutrition of plants, esp. submerged plants. In sum, it is believed that aquatic plants slightly prefer ammonium, yet in most instances, plants grew best when both ammonium and nitrates were available.
> The issue is not that simple just to say 'assimilating ammonium is less demanding energetically'. There are circumstances which must be included into account.


Share them. I’m keen.

The obvious caveat to every single post ever written by every single hobbyist is that things cannot be generalized to every species. 

Certainly, the natural environment will dictate the mechanisms present in a plant. 

I don’t dispute that there exists an optimal ratio given a particular species. However, it wouldn’t make much evolutionary sense if the mechanism did not exists: it could be less efficient and cost more energy or even be unable to keep up with any demand unless metabolic rates were increased. 

I would be rather interested - leveraging Leidbig’s - if we could compensate any of the observations by supplementing higher co2 levels and/or all nutrients associated with the mechanisms —- I say co2 as undoubtedly, it has the highest probability of making a difference.

No matter how you slice it, if you don’t provide the exact amount for a fixed moment of time, there is an associated cost (and that will be energy) — glucose, co2, etc. 

Josh


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## _Maq_ (23 Jul 2022)

JoshP12 said:


> The obvious caveat to every single post ever written by every single hobbyist is that things cannot be generalized to every species.


In fact, plants differ by outer appearance much much more than by their physiology. Proteins and enzymes are largely the same in all higher plants. The reactions they execute are the same, and so are the energetic budgets.


JoshP12 said:


> I don’t dispute that there exists an optimal ratio given a particular species.


There's much more to that. External conditions existing in every moment can influence the energetic balance of many processes. Par example, while uptaking nitrate, a proton is co-transported. That is energetically 'cheaper' in acidic environment - full of protons. On the other side, when ammonium is taken up, a proton is exported. That is easier in basic environment. Similarly, the presence and intensity of light, the presence and concentration of certain other ions, even the concentration of CO2 influence the plant's choice at every moment. (That's why Diana Walstad's statements on this issue are primitive and scientifically incorrect.)


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## JoshP12 (23 Jul 2022)

_Maq_ said:


> In fact, plants differ by outer appearance much much more than by their physiology. Proteins and enzymes are largely the same in all higher plants. The reactions they execute are the same, and so are the energetic budgets.


These are very detail-oriented statements. 

Two bodies also have the same insides … yet they function completely different under different conditions. 

Energetic budgets for the specific mechanisms may be unique, but it is not so simple. You require certain constituents, you have reaction rates, you have concentration gradients affecting the efficacy and yields of these reactions. 

There's much more to that. External conditions existing in every moment can influence the energetic balance of many processes. Par example, while uptaking nitrate, a proton is co-transported. That is energetically 'cheaper' in acidic environment - full of protons. On the other side, when ammonium is taken up, a proton is exported. That is easier in basic environment. Similarly, the presence and intensity of light, the presence and concentration of certain other ions, even the concentration of CO2 influence the plant's choice at every moment. (That's why Diana Walstad's statements on this issue are primitive and scientifically incorrect.)

I suppose we should add the other caveat to every post ever written - it depends on the environment and is unique to all that stuff. 

This is an interconnected web and dynamic system — 

Thanks for your marchner post ps. Won’t take it at face value — not sure it makes an evolutionary sense to negate the ability entirely … the efficacy of the mechanism sure … but a system has access to different forms of N even if you just “dose” NO3 … decay … substrate … fish … etc.


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## _Maq_ (23 Jul 2022)

JoshP12 said:


> Won’t take it at face value — not sure it makes an evolutionary sense to negate the ability entirely


The enzyme which would enable such reaction is known to exist in bacteria but not in higher plants.
Maybe it would come as a surprise to you, but there are many seemingly good things that higher plants *cannot* do.


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## John q (23 Jul 2022)

_Maq_ said:


> View attachment 191359
> Taken from Marschner.


Thankfully I don't run my tank on this theory... 
I've suggested plants can convert amonnia to no3. You've quoted me a quack paragraph stating plants don't excrete  urea..  to quote monty python....  I fart in your general direction sir.


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## _Maq_ (23 Jul 2022)

JoshP12 said:


> Share them. I’m keen.





Taken from Britto, Kronzucker - NH4 toxicity in higher plants. A critical review [2002]



Taken from Brix - Nitrogen nutrition of Canna indica. Effects of ammonium versus nitrate [2010]


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## JoshP12 (23 Jul 2022)

_Maq_ said:


> The enzyme which would enable such reaction is known to exist in bacteria but not in higher plants.
> Maybe it would come as a surprise to you, but there are many seemingly good things that higher plants *cannot* do.


Not surprised. 

Cheers,
Josh


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## JoshP12 (23 Jul 2022)

_Maq_ said:


> View attachment 191369
> Taken from Britto, Kronzucker - NH4 toxicity in higher plants. A critical review [2002]
> View attachment 191370
> Taken from Brix - Nitrogen nutrition of Canna indica. Effects of ammonium versus nitrate [2010]


Pretty sure I’ve said all this …


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## ElleDee (23 Jul 2022)

Y'all, I don't always agree with @_Maq_ , but the fact that plants uptake nitrate and then have to reduce it to ammonium to use it, not the other way around is super basic plant science and highly conserved across plant lineages. There are so many things that vary by species, including which nitrogen source is preferred, but this a very fundamental building block of how plants work.


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## John q (24 Jul 2022)

ElleDee said:


> Y'all, I don't always agree with @_Maq_ , but the fact that plants uptake nitrate and then have to reduce it to ammonium to use it, not the other way around is super basic plant science


Yeah not quite sure what I was thinking last night. Heartfelt apologies to @_Maq_


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## dw1305 (24 Jul 2022)

Hi all, 


ElleDee said:


> but the fact that plants uptake nitrate and then have to reduce it to ammonium to use it, not the other way around is super basic plant science and highly conserved across plant lineages.


<"That one">. 

I really <"enjoy these threads">, and I think the research done by @_Maq_ , @Geoffrey Rea & @Roland is invaluable, but personally I'm really not too bothered about which <"form of fixed nitrogen"> we give our plants. I can't imagine any of us are ever going to <"add enough TAN"> to cause plant issues.  Additionally, with certain provisos, we can estimate the amount of stored nitrate (<"luxury uptake">)  by <"plant colour">.

I've got a method that works for me, just ensure your <"dissolved oxygen supply"> always exceeds your (potential) <"Biochemical Oxygen Demand (BOD)">. I just think plants (including some with the <"aerial advantage">) are the <"easiest way of doing this">. 

It isn't <"very exciting">, but <"it works"> and is <"accessible to every-one">. I want people to keep <"successful planted tanks">, because planted tanks make the <"rest of aquarium keeping so much easier"> and more enjoyable.

cheers Darrel


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