# Ammonium, algae and plant nutrient ?



## scriptors (16 Mar 2009)

Hi people, this is my first post ... I hope not too hard questions   

About Ammonium adsorbium:

plant and algae have the same minimum level necessity of Ammonium or it's different ?

I think plant have minimum level more hight than algae necessity but I can't find research about.

Sorry for my bad English, I try to explain with numeric data (just casual numbers):

I think plant require minimum 0.5 mg/l of NH4+ for adsorb Ammonium and not Nitrate, also algae need minimum 0.01 mg/l of Ammonium for use it ... so if I delete Ammonium from the tank I delete 'all' algae first nutrient.

Some about ?


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## aaronnorth (16 Mar 2009)

hi & welcome.

Plants & algae prefer NH4+ over nitrate, when the levels are below 0.5mg/l NH4+ the plants begin to use NO3 instead.
I am unsure on the minimum levels for algae, however i am inclined to agree with you that it is 0.01mg/l as algae can act much quicker than plants, even when there is a small NH4+ spike when disturbing the substrate etc.you will soon see algae growth appearing.
So when removing all ammonium, yes you will stop algae growth although some algaes can be brought by poor CO2 such as black brush algae.
It is also impossible to remove all NH4+ otherwise the bacteria would die off. Obviously fish are producing it constantly.

HTH, Aaron


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## scriptors (17 Mar 2009)

Well, thanks for reply   

But ... I'm difficult to convince easly   

The 0.5 mg/l limit from which scientific research are came ?
Have you some link ?
Have you made some research about ?
Have you make some repeatable test about ?

Sorry, but I know, aquaristic users, usually make some 'teory' without scientific underground but just from experience and supposed theory (and usually they are discussed and upgraded ... I dosing more NO3 and PO4 ... for many time marked like only algae responsable)

Of course this my are NOT like confutation of your answer but just for investigate more about

ps. I hope my bad English not make 'strange' misunderstanding ... I don't like polemics


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## plantbrain (17 Mar 2009)

Well, there's one reference for Elodea suggesting that range of nutrients for each form of N.
http://keur.knaw.nl/21259/1/21259.pdf

Some issues are present with the study for folks making th assumption.
1. The NH4 was not maintained at 2ppm during the entire course of the test.
2. PO4 and other nutrients also whre not maintained at the higher levels.
3. CO2 was not added
4. Higher light was not added.
5. NO3 needs to be higher than 5ppm and kept high, like the NH4 at 2ppm for the entire test.
6. The test was only for 96 hours............
7. Plants can and will adapt some to difference species of N. This adaptation needs done prior to the test. This is particularly true for NO3, much more so than H4, thus this could skew the data/results.

I agree, given a choice, many species will use NH4, but it must be converted into amanio acids rapidly. This requires lower levels of NH4 and also the carbon skeletons for the amino acids.

So if you are low on CO2..............or add too much NH4, it will inhibit the plant. NO3 is relatively non toxic on the otherhand but the plant needs time to repond to higher levels of NO3 ppm in the water to gear up their enzymes. They can easily store large amounts of NO3 in their central vacuole, they cannot store NH4/NO2. 

Algae are similar............

As far algae blooms, the NH4 + higher light (and CO2 perhaps)need much less to gerimate a spore. The issue with vegetative growth is a different question.

I do not think in practical terms folks see much difference betwee KNO3 dosing and Say NH4Cl dosing etc.
Fish waste add plenty of NH4 as it is and we see little difference there vs no fish or lightly stocked tanks.

I think small amouts of NH4 are fine if you are experienced and have lower light, good CO2. Should not do much harm as long s you do not dose that much, say no moee than 0.2-0.4ppm per day. Max uptake migh be about 0.8pm for higher light. 

It's a bit like playing with fire and you do not get much, if any gain from this. I just use fish waste and KNO3 and I get awesome results, I've tried to improve it via NH4, but found little evidence it offers any significant difference.

If you mess with CO2 and add NH4 with higherlight, it's a good recipe for algae blooms.
But is dependent on light and CO2 as well, whereas NO3, not nearly as much if at all.

It's also very toxic and folks have a lot of sloppy habits and end up tossing in way too much thinking more is better. Then they will blame me  

Regards, 
Tom Barr


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## aaronnorth (17 Mar 2009)

scriptors said:
			
		

> Well, thanks for reply
> 
> But ... I'm difficult to convince easly
> 
> ...



The information i posted i got from Diana Walstad's "Ecology of the planted aquarium"
Here is a paraphrased quote about the method used on Elodea Nutallii:


> Plants (0.5g dry wt) were placed in 1litre of filtered lake water, containing 2mg/l of NO3-N and NH4-N. concentrations were measured at 4, 8, 16, 32 and 64 hours. Each period, 3 tanks with plants and 3 control tanks without plants were used. The control tank showed little loss of either NO3-N or NH4-N due to bacterial processes.



if you are wanting to convert the NO3-N into NO3 then 2 x 4.4 = 8.8ppm
if you are wanting to convert the NH4-N into NH4 then 2 x 1.22 = 2.44ppm

You dont really need those calculations but some people sometimes ask for them  lol.

I dont conduct any "proper" experiments with controlled variables etc, but Tom may be able to help you out some more.


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## scriptors (18 Mar 2009)

Thanks, now I need some time to translate and study about   

I don't want to add NH4+ into my tank, I only think about this 'idea' for reduce algae to zero (apply it in a new tank for have more example of what I think) :

imagine I have one tank with only plants and just some little fish and more Caridina like Red Cherry ... or imagine only one planted tank without fish

my doubt about are 
1. I dont' need bilogical filtration (excluding biofilm on all tank surface ... because it need more time to generate)
2. if I have one 'best functional' biological filter (internal or external) and I reduce to 'about zero' NH4+ (Ammonium) I haven't algae prolification and need only to Add KNO3 (for example) like only form of N macronutrient

why ?

case of 1. because plant use also all NH4+ (few dead leaves of plants) like 0.01 mg/l of NH4+
case of 2. because 0.01 mg/l of NH4+ are not used by plants and only used by algae, so this few concentration are only algae fertilizer ... or bilogical filter food

ps. of course in my tank are present all other nutrients for plant and algae, I think NH4+ like limiting factor in growth of algae because algae have spendibile less energy for processing NO3

of course it's impossible to have zero NH4+ mg/l in tank, but it possible to reduce it by improving best biological filtration of tank

I hope to make one readable post in my poor english


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## gratts (18 Mar 2009)

> Plants & algae prefer NH4+ over nitrate, when the levels are below 0.5mg/l NH4+ the plants begin to use NO3 instead.



Where did you get the 0.5mg/l figure from?
Surely plants will use any ammonia if it is present - even just small background levels? I don't see why they'd suddenly stop using it when it drops below 0.5, or 0.4, or 0.3..


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## scriptors (18 Mar 2009)

it's like my same questions ... but ...



			
				gratts said:
			
		

> ... I don't see why they'd suddenly stop using it when it drops below 0.5, or 0.4, or 0.3..



when/if 10mg/l of NO3 are present into water tank


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## aaronnorth (18 Mar 2009)

gratts said:
			
		

> > Plants & algae prefer NH4+ over nitrate, when the levels are below 0.5mg/l NH4+ the plants begin to use NO3 instead.
> 
> 
> 
> ...



see my above post for more info, i got it from Diana Walstad's "ecology of the planted aquarium"
Why? i am not too sure, perhaps plants cannot detect or use NH4+  if it is below this level


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## aaronnorth (18 Mar 2009)

> imagine I have one tank with only plants and just some little fish and more Caridina like Red Cherry ... or imagine only one planted tank without fish
> 
> my doubt about are
> 1. I dont' need bilogical filtration (excluding biofilm on all tank surface ... because it need more time to generate)
> ...



I am unsure of what you mean in this post. Are you asking what is the best way to keep NH4+ to a minimum?


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## aaronnorth (18 Mar 2009)

Here is more or less the same information as what is in the book if you are interested.


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## scriptors (19 Mar 2009)

For me it's important to know if really plant need one 'minimum' level of NH4+, before use it.

If it's true then the competition of, biological filtration and algae, for NH4+ are really one anti-algae instrument ... if it's false biologic filtration are one competitor for plant and algae and we must investigate more about algae reduction  :? 

Here some Diana Walstad consideration about and, it seems plant use NH4+ in every concentration possible  :?: 

But I have some doubt about (and we use much different plant in our tank)


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## aaronnorth (19 Mar 2009)

I forgot to add the link in my last post  sorry
http://www.bilyap.com.tr/magazin/mag3/concept1S3.php


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## plantbrain (19 Mar 2009)

I think you folks are likely missing the big picture, this is not a large factor in growth, say compared to CO2 enrichment or lighting differences in intensity.

As long as the plants are not limited for N, no matter where it comes from, they will do well.

So you can say they prefer something, but it has little impact for us and potentially lead folks to over dose, which they always do at some point.

Also, let's look at ADA aqua soil release of NH4.
It gets fairly juicy.
Some plants melt and die back due to the higher NH4, some do well. 
After a month or so, you can add fish etc, about the same time it takes to bacteria to take over and less leaching. 
They suggets every other day water changes, or every 3-4 days or so for that first 1-2 months.

The plants still do very well later also without all that NH4...........so.........

So why doesn't the plant biomass remove all the NH4 in those tanks really fast?
Some might say the rates of NH4 leaching are too fast etc.
Still, why water change if this is true?

I think at really low levels of NH4, it's fine, plants will gobble up the NH4.
At higher levels and ample levels to supply to plants, NO3 offers a better trade off.
You do not get that muh difference in rates of growth really in practical temrs and you are not interested in simply having faster/higher rates o growth, just stable growth, which KNO3 is much easier to add and provide in that manner than small amounts of NH4. Which is more toxic also?

So just some practical matters alone would suggest there is a lot more to this than just rates of growth.
If.........we honestly want more growth, we can add CO2 gas, or more light, or both etc.

Those will give you more yeild, than this. And you can simply add more fish etc and feed them for NH4 sources.
The rest can be supplied via KNO3.

Regards, 
Tom Barr


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## scriptors (23 Mar 2009)

I make some study about and, for now, I think plant and algae prefer NH4 if this is present without upper or low limits (of course hi percentage of NH4 are dangerous and toxic and it's a bad idea to insert it into tank) 

Here:  http://weriguam.org/docs/tr_10.pdf one new question and interesting things. It's write that percentage of NH4 inhibits NO3 adsorption so first plant use NH4 and then NO3

This explain how, some time, plant have problem of N deficiency  if N are present (KNO3 dosage)  :?: 

ps. all my question are only about HOW, biological filter - nitrification, can reduce NH4 and algae problems (I'm sure many algae problem can solved by NH4 reduction from one best performed biological filtration, for example one correct water pump velocity)


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## plantbrain (8 Apr 2009)

Thanks for the pdf, 

In that paper, they study non adapted plants, they just add it and then measure over 48 hours of exposure.
In aquariums, most plants are well adapted to the conditions.

There is a lag time for NO3 but once it starts, does adding NH4Cl stop it once again and inhibits it?
Also, you can see much different uptake rates for various plant species.

You also are left with the linear model for NH4 uptake or a MM model. In both cases, you have to add a fair amount of NH4 to do this. You can add a lot of NO3 on the otherhand (several day's worth/supply).

You can and may use NH4 at high levels using flushing methods and daily large water changes with no ill effects.
Say about 0.8ppm per day.

I think after some time, you can modify this and reduce the NH4CL dosing some to suit the demands, while the NH4 uptake appeared linear, for how long does that occur?

Clearly once the plant has adapted and has all the non limiting N, this has to slow down otherwise the plant will die from NH4 poisoning, they use NH4 to kill plants BTW as a herbicide for this very reason.

So clearly, there are limits here.
This study, nor others address these types of questions.
So it really remains unknown, the evidence is not conclusive.

I'd say there's some evidence on both sides.
But the real question that is important: does NH4 as a source in practical terms, increase plant growth significantly?

How is this N uptake rate influenced when CO2 ppm' are changed/limiting/excess or if they are stable over time?

That's an interesting question. ... and one that seems to be most relevant.
The CO2 carbon supply raises it's ugly little head. Emergent plants do not have this issue, so often they are better suited to answer such questions.

Light is in ft candles, this can be modified however.

the author points out that this might be important in low nutrient systems(NO3 vs NH4), but as aquarist/hortuculturist, we do not have that problem or issue, we can have any range of NO3 or NH4 or both. So the relative importance of this only becomes crucial when you run things really lean. In non CO2 dosed tanks where the main N input is fish waste/food, reduced and bound N, moistly as NH4, as NO3 is very mobile in water.........this seems like the main player.

At high CO2, the residual ppm's of NO3 can be saturating, say at 20-30ppm. At that concetration or higher, the uptake is independent of concentration. An eqauilivlent ppm of NH4 will be about 3.5x less.

So 4-5 ppm of NH4.   The curve of the NO3 is fairly linear once it gets going to about 18-20ppm.
NH4 is linear mostly.

So 4-5ppm is fairly good for a similar amount.

A daily rate of uptake, assumig n that all NO3 and all NH4 dosed gets to the plants:

1-6 ppm of NO3, with 3-4ppm being a typical max.
0.3ppm to 1.8 per day, with a typical range of 0.8ppm-1.2ppm

You can see that if the NH4 builds up and the bacteria does not respond, you are in trouble using NH4 vs NO3.
Eg if the CO2 goes sour etc.

And you keep adding the NH4.

This is my concern. 
Newbies doing it and everyone also bugs me, I know someone will kill their fish doing this, when the gain is still pretty questionable.

I've had better gains by focusing more on reducing Nh4 and dealing with CO2 really well.
You get maybe say 30% more growth with NH4 vs NO3 under some conditions.
But............you get 1000-2000% or more, with good CO2, or say just 300% better with say 15ppm vs 35ppm of CO2.

The greatest N demand is for carbon fixation in the enzyme Rubsico.
So plenty of CO2= less N demand and plenty of ATP's and NADPH's for "work" instead of going after CO2.
You can add it and try it, just be careful in what you conclude. If you run higher lights and are not that good with CO2, this might not be the wisest thing to do. 

The above is a good estimative index of NH4, I'd suggest using a daily, even 2x a day dosing, like if you feed the fish 2x daily, you can squirt a bit in(I'd also go liquid like traces to dose more precise amounts).

I might be wrong about algae and NH4 signaling, it might be some dependence on CO2 as well.
The two together seem to wreck havoc, CO2 alone can also. Adaptive issues, species differences and time might also lead us to some wrong conclusions about preference. 

It's not an easy thing to get at.
A good study would use N15 and follow who got what as far as a NH4-15 and NO3-15 labeled sources and see if the induced algae spores took the labeled NH4-15. 

energetically, there's no argument that NH4 is easier, what the issue is, under our situation and what is best for the method/us/the fish/plants really that much more significant to warrant using and managing something much more volatile??

That is the meat of the issue, the trade off, is it worth it?
Do I want more plant growth? More effective N use?
Maybe not, maybe I have lower light to reduce the issues and work, growth.
Adding more might not be my goal.
As long as the plant has N from some source.

These issues have not been consider thoroughly IMO.

Regards, 
Tom Barr


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