# Dosing with Ammonia and Urea



## JamesC

Decided to open a new thread on this very interesting subject rather than carry it on in the Good Algae Article thread - http://ukaps.org/forum/viewtopic.php?t=905

Here's what been said so far:



			
				George Farmer said:
			
		

> ceg4048 said:
> 
> 
> 
> 
> As George alluded to, some vendors use ammonia salts as their source of N, which I find completely astonishing. Probably the levels are low enough if dosed properly, but I don't see the point. I might be missing something so I want to study this some more.
> 
> 
> 
> 
> Let us know how you get on mate.  I read somewhere that plants have an 'easier' time using it for their N source than KNO3.  I'm no biochemistbotanist though...
> 
> But I know I don't get algae.
Click to expand...




			
				JamesC said:
			
		

> I looked at ammonia additions to tanks a while ago. A few notes for you.
> 
> Seachem Nitrogen uses guanidine and potassium nitrate as their source for N. Guanidine is similar to urea. I think I'm correct in believing that plants can utilise the Urea but algae can't - may need to check on this.
> 
> Tropica use ammonium nitrate but I think it is bound up somehow so it's not like adding ammonium salt - need to confirm this.
> 
> Some people have been exprerimenting using urea with good results, but others haven't.
> 
> A thread just started on APC might be of interest - http://www.aquaticplantcentral.com/...aquarium-plants-preference-ammonium-over.html. Follow Freemann's link to the Barr Report as well.





			
				ceg4048 said:
			
		

> Hey James, thanks for that bit of clarification. I remember trying Scott's terrestrial fertilizer which contained urea and ammonium nitrate. It worked well as long as I had a huge biomass, dosed small amounts and kept up the water changes, but it was living on the razors edge and any other mistakes I made seemed to be exacerbated by using the product. I was under the impression that urea broke down into other components including ammonia, but if urea is not available to algae then that might explain things. I'm very interested in understanding the mechanism of how TPN+ binds the ammonium nitrate. Can't argue with Georges success using it.   8)
> Cheers,



I'm going to look into this a bit more and I might even test with dosing some urea to see how it goes. To what I can gather it works best in a fully planted tank with CO2 and plenty of all the other nutrients.

Urea needs an enzyme called Urease to be broken down.

Dosing is still fairly critical because urease is naturally occuring so the Urea will be broken down in the tank creating ammonia.

To what I can gather dosing Urea may benefit soft water tanks more than hard water tanks. In the link I posted above there is talk to why this may be so.

James


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## ceg4048

Excellent! Thanks for that James. I've been studying the APC thread and what baffles me the most is the post #9 in that thread where the poster reports stunting/dying and yellowing of the plants when dosing KNO3. I've seen just the opposite - and that's been in RO water at times and tap at other times. I can revisit this though. James any idea where to source the urea granules?

Cheers,


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## JamesC

There's been some debate about high NO3 levels in water with a very low GH. Some people have no problems while others have no end of problems. The main problem plant seems to be Alternanthera Reineckii which some have said suffers with NO3>10ppm and GH<4. Tom Barr has just finished an experiment that shows that this is not the case. But Tom used ADA AS which the other people didn't so that might explain something. I know I have always had problems with Alternanthera reineckii  in my silica sand substrate under both EI and the PMDD+PO4 dosing I do now. Strangely it's only Alternanthera reineckii  that struggles, everything else grows really well.

This is one of the reasons I looked into urea dosing as I'm not convinced it's anything to do with NO3 levels. I've actually just brought some more Alternanthera reineckii to see if I can grow it now. Luckily my wife works in the labs at a college so I can get hold of most chemicals. Got some Urea coming home tonight  . Won't start using it for a while though as I'm away next week. I'll update when or if I start dosing. Need to go and spend some time to see what levels others are dosing first, but am well busy at the mo so will have to wait.

Oh, I can grow Alternanthera reineckii really well actually by just lowering my lighting right back and slowing everything down, but I like to have a challenge and work out the reason's why things happen.

James


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## George Farmer

You crazy scientists - I love it though!


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## ceg4048

JamesC said:
			
		

> ...I know I have always had problems with Alternanthera reineckii  in my silica sand substrate under both EI and the PMDD+PO4 dosing I do now. Strangely it's only Alternanthera reineckii  that struggles, everything else grows really well.
> 
> 
> ...Oh, I can grow Alternanthera reineckii really well actually by just lowering my lighting right back and slowing everything down, but I like to have a challenge and work out the reason's why things happen....
> 
> James



Hi James,
                 I'm having a twilight zone experience again. I mean, A. reineckii has always been a weed for me whether in RO, tap or RO+tap. The plants I have now I got from Pets-are-home where, following beeky's advice, I got them to give me the surface scrapings from their plant holding tank for free. I chucked the slivers in the tank and never looked back. It grew like gangbusters and I even sent some to daniel1983 who chucked it in his tank and never looked back (from all accounts) http://www.ukaps.org/forum/viewtopic.ph ... c&start=50

After reviewing that Barr thread I saw where the original poster was having difficulty with distorted leaves and was blaming NO3 for it, which I thought was unbelievable. NO3 is being blamed for stunted growth, yellowing of leaves and malformed plants all in the same lifetime. I may be one of NO3's last defenders!

I'm going to fire one shot in response. Now, there is some yellowing on the L. aromatica. I think that's normal coloration but I want to keep an open mind. Maybe urea will give me a darker green? The other thing is the A. reinekii leaves are not flat, but are a bit crinkled. Could that be the problem? I always thought it was normal.   




Cheers,


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## George Farmer

ceg4048 said:
			
		

> Now, there is some yellowing on the L. aromatica. I think that's normal coloration but I want to keep an open mind. Maybe urea will give me a darker green?



That's 'normal' IME.  Then they go red as they get nearer the light.

But what is 'normal'?!   

Super thread guys.   Keep up the good work.


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## JamesC

I've decided to give dosing urea a go and see if there are any differences. Looking at what other people have experimented with on other forums I have decided to go with 0.5 ppm of urea per day. I have reduced my daily NO3 dose so that the total amount of Nitrogen added remains the same. 

The other change I've made is that I normally add the macro's before I go to work in the morning but now will add them when I get home from work when the plants are in full photosynthesis. The thinking behind this is is that if I add the urea in the morning the biological filter will remove the urea before the plants have a chance to use it. But adding it after the lights have been on for a couple of hours will make the urea instantly available. That's the theory anyway.

Today, Saturday is the first day of dosing so I'll keep updating this thread with my observations.

James


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## plantbrain

Be prepared to get burnt by dosing NH4.

We went through this in the late 1990's and I suppose all cohorts of aquarist tend to as they go through the hobby.

There are other factors here.
It's not as simple as you are making it out to be.

Fish loads add plenty of NH4, provided you actually keep fish
I have either packed tanks or hardly a thing in there.

Now you can do a few things to see how NH4 influences tanks, plant growth etc, it's not just this one piece meal thing that applies to every tank under all conditions.

There are obvious factors that influence results:

Light intensity- huge differences in algal responses
CO2, turn it off and see.
Filters, take this off to see how much NH4 is being oxidized by bacteria(hint: a lot), wait 4-8 weeks and then see......
Current, reduce this and see.

Plant biomass/filter cleanings water changes etc.

If you do daily 50% water changes, you can dose .6-.8 ppm of NH4 via NH4Cl without an algae bloom, but again, daily water changes.....

Filters are cycled using ammonia, what do you think a filter will do if you add more fish to the tank slowly?

Now what about NH4 added slowly?

You need a method to distingush what is occurring with the plants, *not* the filter and other factors.

My point is simple, why is adding more fish any different then than adding NH4 and urea?

Is it?

I do not think it really is............and we all like more fish.

I have ADA AS, but the results with the NO3 dosing are no different.
I have the same growth patterns.

NO3 is a lot safer as far as toxicity than NH4 also.
Personally, I'd rather have more fish and feed them better if I want more NH4 in there.

And you really cannot underestimate that filter.
It's a really obvious thing.
At least to me.

So, if you think it's all plant, try removing the filter for a time, 4-8 weeks is often enough, add more light etdc.

Dose away
Question is, "do you feel lucky"?

BTW, if you do this, be prepared.

If you assume that adding NH4 will work well, then  you use nothing but fish as the source for N.

Can you over load the tank using fish over stocking and induce algae?
Yep.

In a non CO2 tank, the demand is low, so fish waste alone meets the demands.

As we increase and amplify growth(hardly natural), we need to switch to less toxic forms that we can add with less trouble and error.



Regards, 
Tom Barr


Regards, 
Tom Barr


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## ceg4048

Hallelujah, sanity restored...   

Thanks Mr. Barr, but can you comment or explain why the TPN and ADA fertilizers should choose to use NH4 and how it would be bound to avoid algae?

Cheers,


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## JamesC

Well I've now been dosing 0.5ppm of Urea daily now for nearly two weeks. Still early days but one thing I've noticed is that the new growth of my Rotala Macrandra is looking really good, more pink and fuller than before. The Alternanthera Reineckii ''roseafolia'' also looks as though new growth is healthier. As it's not such a fast grower I'll need to give it more time.

Most importantly fish and shrimp are behaving as normal and there are no signs of algae. Water is still crystal clear as well.

I'll update again in a few weeks.

James


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## GreenNeedle

Just a note.

From my time at William Sinclair (J Arthur Bowers/Silvaperl etc) all composts have Urea as the N in them so quite a few of our members may have already stumbled upon some problems / benefits that apply to this situation.

Andy


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## ceg4048

OK, been sniffing around at some of the agricultural sites to see what the advantages of urea are. Urea is available, by the way, at Garden Direct. 1/2 Kilo for Â£3.25 plus shipping - http://www.gardendirect.co.uk/urea-p-224

The nitrogen content is almost 50% so I can see why this product is surpassing even ammonium nitrate as a crop fertilizer. This compares to KNO3 which is only about 14% nitrogen.

What I'm still a bit confused about though is I couldn't find any description of what happens when it dissolves in water. The agricultural sites discuss the breakdown of the compound in soil, and that the hydrolysis requires the presence of a soil enzyme called Urease:

CO(NH2)2 + H2O + urease -> 2NH3 +CO2

It's not clear to me whether an aquatic plant absorbs the compound in it's entirety and then breaks down the urea internally or whether the breakdown into CO2 and NH3 can occur directly in the water without the presence of this urease enzyme, or whether the compound breaks down according to some other formula. Can you shed any light James?

The next question therefore is: can you achieve the same growth improvement by simply tripling the KNO3 dosage? That would be the next test I would think.

It's also not clear, as plantbrain noted what percentage of the urea product breakdown (if indeed NH3 is released into the water column) is taken up by the bacteria and converted to NO3. Can you measure this accurately?

Cheers,


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## JamesC

Some very good questions. Plants don't, I believe, take up urea directly but take up N in the inorganic form. Urea once in the tank will fairly quickly convert to ammonia by either urease or micro organisms in the substrate. It could be possible that bacteria in the filter will do the same but I'm not sure of this. I would guess that urea would convert to ammonia over a period of time which is better than a single large dose of ammonia. As Tom suggested adding more fish to the tank would most likely do the same thing.

To what I can gather from other posts on forums some plants may do better with NH4/NH3 and NO3 rather than just NO3. This is just speculation though. But as some of the major brands add ammonium compounds to their products made me think about it and give it a try. If it has a positive benefit on some of my plants then great, but if it ends in total disaster then I know not to do it again.

I would love to know why Seachem, Tropica, etc use ammonia compounds in their nitrogen products if everyone says it's so bad. There must be more to it than I know. They say it's because plants prefer ammonium compounds to nitrate, which is probably true, but then if plants can use nitrate just as well then why take the risk of adding ammonia?

James


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## ceg4048

JamesC said:
			
		

> I would love to know why Seachem, Tropica, etc use ammonia compounds in their nitrogen products if everyone says it's so bad. There must be more to it than I know. They say it's because plants prefer ammonium compounds to nitrate, which is probably true, but then if plants can use nitrate just as well then why take the risk of adding ammonia?
> 
> James



James I've been thinking about this question because it baffles me as well. The only conclusion I could draw is cost. If you look at the Garden Direct pricing 1/2 kilo of urea is Â£3.25 whereas a 1/2 kilo of KNO3 is Â£5.25. Further, look at the higher N yield - 46% N versus 13% N, almost 4 times as much for urea. Almost certainly, whatever ammonia products are being used in the commercial N products have a less expensive production cost.

Meanwhile, back a the ranch I decided to goad you into committing an error by showing what urea will have to beat. If it can grow A reineckii "roseafolia" better than this I'll be convinced:



 



Cheers,


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## Ray

Very nice experiment James - thanks for sharing your results.  


			
				ceg4048 said:
			
		

> The next question therefore is: can you achieve the same growth improvement by simply tripling the KNO3 dosage? That would be the next test I would think.


I think that is the million dollar question - are you prepared to give it a try James after the urea trial period is over?


> The only conclusion I could draw is cost.


I think you've hit the nail on the head there Clive - its certainly the beancounters who have the most influence on what goes in these products not the anti algae guru's...  But James isn't reporting any algae triggered by the urea dosing.  I'm wondering, as the urea breaks down, does it still pass through a form that can trigger algae - on paper it does but we're not seeing what we would expect :?:


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## JamesC

I'm trying Clive. Don't ever think I'll get it as good as yours though as that's one of the nicest specimens I've ever seen.

Even taking the cost difference into consideration I can't believe manufacturers would put ammnoium compounds in their products if it is supposed to be so bad. The amount added to each bottle is pretty small and also they don't actually use urea but guanidine which is similar and also ammonium nitrate I think. 

I have 4wpg of HOT5 above my tank and add urea daily and so far there is no signs of any algae.


I've been doing some more searching on urea and it seems that plants that contain the enzyme urease can utilise the N in urea directly. This does depend on how long the urea stays as urea in the water once added. If it converts to ammonia within minutes then it may not make any difference. I wonder if it's most plants that can utilise urea or just a handful.

James


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## George Farmer

Fascinating guys.

Love the pics, Clive.  Super plant health, bordering on looking artificial!

Is that the rock I gave you at the Festival?


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## ceg4048

Hi George,  
                  Hey, I can rough them up a bit if that will help make them look less artificial... 

Yes that's one of the rocks "appropriated" from the festival! Remember you gave me two? The second is being swallowed the smaller A. reineckii on the right. I'll have to pull that plant out and replace it with something cleaner, like maybe Blyxa or maybe one of those new super-secret Tropica mutants...:idea:


Cheers,


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## Ray

JamesC said:
			
		

> I've been doing some more searching on urea and it seems that plants that contain the enzyme urease can utilise the N in urea directly. This does depend on how long the urea stays as urea in the water once added. If it converts to ammonia within minutes then it may not make any difference. I wonder if it's most plants that can utilise urea or just a handful.


And:


> I have 4wpg of HOT5 above my tank and add urea daily and so far there is no signs of any algae.



(as Cliver already said) urease works like this:

*(NH2)2CO + H2O ? CO2 + 2NH3*

That's quite a nice win for a plant that has urease, a byproduct is CO2 which it also needs - its like a power pill!    Is it possible, as I think James is hinting, that the plant takes on all of the urease and uses the CO2 and metabolises the NH3 all in one go?  If so then there would be no time for any background ammonia to trigger algae.  Assuming urea can't trigger algae this could explain why it is safer than dosing ammonia.

Of course this would be no safer than dosing NH4 directly - I'm willing to bet James' good results are due to increased availability of N rather than anything else and could be duplicated by increased doing of macros :?:


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## JamesC

Ray said:
			
		

> Assuming urea can't trigger algae this could explain why it is safer than dosing ammonia.


To what I can gather algae are not able to utilise urea directly as they lack the urease enzyme.



			
				Ray said:
			
		

> I'm willing to bet James' good results are due to increased availability of N rather than anything else and could be duplicated by increased doing of macros :?:


And you may be correct, but I had high NO3 before from increased EI dosing and CO2 mist blown directly at the plant and this made no difference. This is what has led me down this path of dosing urea. I shall though if this trial is a success remove the urea from my dosing and replace it with the equivalent amount of NO3 to keep total N the same.

James


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## Lisa_Perry75

I was looking for chemical structures to show why the percentage of N changes and found this:-
http://bcn.boulder.co.us/basin/data/BACT/info/NO3+NO2.html
It is a good page with useful information on urea and ammonia. I might add that just because urea has more N %age wise it does not mean it will all be available for the plants. From what I can gather on that web page urea breaks down into ammonia and then oxidises to nitrate.
Urea




Ammonium (ammonia has 3 hydrogens)



Nitrate




And just to blow your minds I thought I'd add the structure of urease, just cos its beautifiul... I'm off to look at the structure in more detail!


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## plantbrain

When you folks add small daily amounts of N, urea or otherwise(NH4),

What do you think happens with the filter bacteria?
Do you think the colonies become larger?
Or smaller?

In other words, adding more NH4 is a bit like doing fishless cycling.
My point is how do you know that the plants are really getting most of it?

You really don't.......

What happens if the NH4 ends up as NO3?

I agree adding NH4 is not an issue as long as you at low levels, have no so intense light, decent care and stability etc.

Everyone that's done this gave up and went back to normal routines.
Or they decided to add and feed their fish each day.

You can measure and weight the amount of fish food to get a good idea how much NH4 comes from the fish waste.

About 90% is excreted, and 10% at best is retained in the fish.

So 90% of the fish food ends up as NH4 or is converted by bacteria to NO3. Urea is pretty quickly turned to NH4 in water.

Folk's use to use Schultz's African Violet drops here in SF the late 1990's.
A few algae outbreaks caused them to stop and switch to fish.

Seems simpler and less risk to just feed the fish.
I was never able to measure any growth rate differences.

Anyway, adding NH4 via the sediment is wiser and easier.
ADA As has it. and the outside of the grains quickly are oxidized by bacteria, but the roots can get at the interior parts of each grain that have the NH4 still in there.

If ADA As was hard, not soft, it would be too tough to have the root get at the NH4.

I think that is the main thing you see in ADA As and mud/soil sediments.
Water column dosing seems not worthwhile.
I think you end up making a much larger bacteria colony is all.

Anyway, plants CANNOT store NH4 inside, they can and do storage lots of NO3.

So you can either dose it daily, small little bits, risk toxicity, algae etc, or just add a few more fish.

Do we see dramatic differences based on fish loading?
No, not really.

So why do you think this would be much different?

Tell you want, keep adding progressively more and more NH4, urea and or fish to your tank.

See how much it takes to break the system.

It's going to be pretty variable.

Also, try removing your filter. 
Try to rule things out.

You'll learn.


Regards, 
Tom Barr


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## JamesC

I have now finished my little experiment with dosing urea and can honestly now say I have noticed no difference to when I dosed no urea. Plant growth and appearance are exactly the same. Also I'm happy to say I didn't get any algae with adding the daily amounts of urea.

I shall now return to my normal urea free dosing.

James


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## ceg4048

James,
          Any theories of why the APC poster would have reported such dramatic differences? I still wish I understood whether the urea was being converted via nitrification or being consumed more directly as NH4. From Mr. Barr's explanation it sure seems like it is ultimately an NO3 uptake. Were you able to take any measurements? How did you arrive at your ppm values and do you think you would have the guts to up the dosages?

Cheers,


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## JamesC

It's very hard to know what's going on but I have a suspicion that the urea is very rapidly removed by the filters before the plants have any chance of getting access to it. I'm always a little sceptical about what people say with their dosing schemes which is one of the reasons why I like to try different methods to see what the results are. 

The amount of urea used was a value that I had seen other people use. I often go away for weekends so when I do I just dose the weekend amount before I leave. Seemed to cause no problem that I could see. Don't think I'd want to dose too much urea just in case.

Maybe urea dosing works better on lower light systems with no or few fish.

James


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## plantbrain

James, using urea on lower light systems of any type will = less algae issues, this is true for ANY treatment.
I'd be careful not to assume that it's for only a lower light system. 

If a test is really what folks are interested in, then setting a wider range of light levels or a high/very high light level would be the best to see how much, how long to destabilize things.

If you use the rational or logic that suggest if you can keep things easily stable at very high light, high CO2, high nutrients, then a very wide range is allowable at less light intensity, correct?

You can obviously get away with a lot more wiggle room at less light for most any treatment.
This is a simple logic that allowed me to use EI dosing to target any aquarium without much issue even with a wide range of light values.

At 4 W/gal, I could not add much NH4.
I had GW otherwise.
I could easily kill the GW with a UV, then repeat the test again after a few weeks to see and get more replications from the same system.
Then I tried adding progressively more fish.
Same results but a few different species of algae.

At low light, urea is fine, but so is adding more fish  
If you add high fish loads to high light tanks, what are the odds the tank will be more stable vs fewer fish?

I think many folks over look a lot when they rush to judgment and set up so called "test".
You need to be careful and make sure you know as you try and answer questions.

You also need to see what types of test you can set up that actually answer your question :idea: 
Many of the test I've done over the years I happened upon and had a small epiphany. But I was suspicious of my results and wanted to be sure.

Later, I've gotten better :!: 

But the idea to test it for yourself and see, rather than bandwagonieering, and suggesting someone's test or claim is right or not and sounds logical is a poor method.

Try it for yourself and see.
Prove it to yourself.
This type of approach and advice helps produce critical thinkers and folks that can answer questions, not merely parrot belief and statements said by others.

Regards, 
Tom Barr


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## plantbrain

BTW, this might help to see what urea does:

CO(NH2)2 - H2O + Urease => 2NH3 + CO2.

So adding it to water only requires urease, which many things in a rich juicy aquarium have.............thus it's rapidly converted to NH3/NH4 and CO2.

Here's a paper on the topic:
http://www.ncbi.nlm.nih.gov/pubmed/17268879

The epiphytes/bacteria and the sediment transform most of it.
Plants take up some, but overall, the bacteria seem to do most of the work.

http://www.staff.kvl.dk/~nogj/Aquatic/Urea/index.htm

Dr Reddy was my professor at UF.
He is the Man when it comes to cycling in wetlands.

http://wetlands.ifas.ufl.edu/publicatio ... -1997.html

Read a few of those.
When you are done, you'll know more than any aquarist about sediments.

I'm not sure why other folks have not bothered to look up things.
I guess they are scared of really learning. 
It's not hard these days with the web either.

However, you still need to know what to look for, how to interpret what you find and apply it.

Regards, 
Tom Barr


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## Aeropars

You guys completely lose me on this every time.... i'll stick to drinking beer and following your instructions


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## JamesC

Some interesting reading there. Thanks for posting Tom. If I had the time and resources I would love to run some trials and learn more, but at the moment I can only judge by what I see in my tank.

James


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## plantbrain

James et al,

Consider running smaller and simpler test on pots or terrestrial terrariums, small dinky tanks etc.
Less work, more rep's. Be creative with the designs.

Most do not have a bunch of tanks to play with, I used pairs and then run blocks over time.
But I spent less time doing scaping as a result.

Regards, 
Tom Barr


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## ceg4048

Hi Tom, OK, it seems as if every time I think I have a grip on one riddle I find that there are ten other riddles unaccounted for. I looked at the first link - the entire article can be found at the SpringerLink site: http://www.springerlink.com/content/m761n307t70t5p07/. The article is mindblowingly difficult to follow but what seems clear is that algae have no difficulty uptaking urea whether it is by direct uptake or by transformation via the "epiphytic biofilms" in the same way plants do. It is stated that "...Previous studies have found that urease enzymes can be intracellular, cell surface bound, or extracellular..." which sounds to me like the transformation can occur above, below or within the plant's tissue structure.

The article also states: "It was found that the urea transformation was 100 times higher in sediment ...compared with the epiphytic activity on the surfaces of the submerged plant Elodea canadensis..." There was some further correlation made between the available surface area of the plants in the aquatic zone being studied and the epiphytic transformation rate, i.e higher leaf square footage yields higher transformation rates.

What is not clear to me though is if the sediment does that much more transformation does that mean that a majority of the urea James was dosing found it's way into the substrate, was transformed by the substrate's urease, and then ejected from the substrate ultimately as NO3 after nitrification? If that is the case does this occur via flow in and out of the substrate, or would this happen at the surface of the substrate and distributed by filter flow? Also, does the filter count as an extension of the sediment in this case?

I looked further into urease and found a cool illustration of the active site of the enzyme: http://www.uni-regensburg.de/Fakultaete ... ease-e.htm

The more I looked at this though the more astonished I was by the explanation that the active site was an area of the molecule where two Nickel atoms are attached to a hydroxyl?  So my question is, if urease is so abundant then it follows that Ni must also be abundant, but how?? We don't dose this so I'm even more dumbfounded. Are there different "species" of urease which use different, perhaps more abundant metals at the binding site?

Any clarification you could offer would be appreciated.

Cheers,


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## plantbrain

Nickel does not need to be that abundant, after all, think about it, that urease enzyme gets used millions of times and only needs a few metal cofactors.

Relative to other nutrients and metals, there's very low demand for it.

Yes, filter bacteria do what sediment bacteria do: transform and use energy and reduced forms of N like NH4 are great sources.

I would not expect a lot of work form the epiphytes on plants, but there's still a lot of them, even if 100 times less.

A simple test, use Riccia in a bare bottom tank with CO2 etc and high light
No  filter, no bacteria really etc, you could dip the plants into diluted Excel to kill bacteria etc and then grow it out.
Or just float Egeria etc in a bare bottom tank.

But yes, it's not this simple nice little system we are playing with here.
The effects we see might be due to increased filter bacteria colonies, not increased plant health.
Big filter colony able to remove larger amounts of NH4/urea= less chance for algae spores to get any NH4 to germinate.

Observations support this view as well.

By using 15N (stable isotope) labeled NH4 or urea, we can measure how much NO3 is transformed by bacteria and how much algae spores/algae adults and aquatic plants get.

This would be a wonderful test, something I've been thinking about for 8-9 years now.
It could answer many complex questions in our tanks.

Just fund me 50-100K$ and give me a year, I'll get right to it
The above study used the transformed products of respiration, rather than following the partitioning of Nitrogen.
I am doing the same type of thing with Excel in plant tissue as they did.

So filter, plants and sediment all are playing a role, I'm not sure how much each part contributes, but the evidence suggest bacteria play a huge role here.


Regards, 
Tom Barr


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## JamesC

I've been thinking a lot about this subject recently again and so have decided to bring this topic back to life. What I want to know is why do the likes of ADA, Seachem, Tropica, etc, all use ammonium or urea compounds in their fert solutions for a source of nitrogen. If it's so bad why take the risk of giving your product a bad name. There must be more to it. I don't for a moment believe they do it because of the small cost difference of potassium nitrate. I have even posted on other forums asking the same question but as of yet not got an answer.

Low ammonia levels don't worry me as I believe that it is beneficial to the plants. I keep lowish nitrate levels which then makes ammonia more favourable for uptake by the plants. This may explain why heavy nitrate dosers have more problems with ammonia as it is less favoured over nitrate. I may do some more testing with dosing urea using the levels of ammonium in TPN+ that I have worked out in this thread - http://ukaps.org/forum/viewtopic.php?f=11&t=3985&start=0.

James


----------



## GreenNeedle

I don't think many  suppliers would worry too much about the price of Pot Nitrate.  Its phosphate supply in its various forms that sky rocketed last year to the point it was darned hard to get for the fert companies without pre-ordering heavy amounts (talking ordering whole year's supplies in advance to ensure supply)

Molybdenum and Molybdate are the other 2 rocketing elements within the ferts industry.

Garden manufacturers use both Pot Nitrate and organic sources in their products!!!

AC


----------



## zig

I don't know the answer.

Here's a link to a german seller that uses ammonium/urea compounds in fertiliser solution for planted tanks, you are probably aware of this already James, posting it anyway just in case it may add something to the discussion.

http://www.drak.de/shop/eudrakon-bottle-p-118.html


----------



## JamesC

Hi Peter,

Hadn't seen that before, thanks for posting. It contains urea + KNO3 + NH4NO3 in these amounts
1 ppm NO3
0.1 ppm NH4
0.33 ppm urea

Interesting that he also states this and I quote


> Due to energetic reasons, it is slightly easier to absorp ammonium than nitrate. But higher nitrate concentrations diminish the ammonium absorption



This is what I've always been led to believe and is why I believe heavy nitrate dosers seem to have more problems with ammonia. 

James


----------



## Voo

I wonder how much Tropica would give away if you was to ask them why they use ammonium nitrate instead of potassium nitrate, and voice your concerns about adding extra ammonia to your tank?


----------



## Voo

Here's an article by Diana Walstad about the uptake of ammonia and nitrates. 

In it she states "Aquatic Plants Prefer Ammonium Over Nitrates" and also "Aquatic Plants Prefer Leaf Uptake of Ammonium"


----------



## ceg4048

Well, the thing is that we have to be very careful on the broad statement as regards inhibition of nitrate uptake by the presence of ammonium. This is very species specific and may not be valid. In just about every botanical journal I've read there was no inhibition demonstrated, and in fact the rate of NH4 uptake very often exceeded the rate of NO3 uptake when both are present. Here is a typical report, although the focus of the tests were to determine the relative uptake of root versus leaf => Ammonium and Nitrate Uptake by the Floating Plant _Landoltia punctata_

Barr's data indicates that the preference is dependent on relative concentrations however, such that at high NH4 concentrations NH4 is preferred while at very low concentrations NO3 is preferred. This could also be species dependent.

In the DRAK shop website that zig provided it is stated "..Ammonium is absorbed instantly and mainly by water plants, but on the other hand, it can not be stored. Due to energetic reasons, it is slightly easier to absorp ammonium than nitrate..." What he is alluding to is that the energy cost for the plant to strip an NH4 ion of it's nitrogen is much lower than the cost of stripping the NO3 ion. NO3 has to be reduced by a chain of various enzymes such as nitrate reductase and nitrite reductase. On the other hand NH4  buildup in the tissues is toxic to the plant so that accumulation of NH4 requires that it be converted to, and actually stored as NO3.

I completely disagree with his contention that the "optimum" nitrate concentration is on the order of less than 10ppm. I mean, that is in complete conflict with my observations. The more nitrate I add the faster the growth, assuming all other nutrients are unlimited, naturally. I see no evidence whatsoever that any plants I've grown respond poorly to high nitrate levels.

I see no evidence that the presence of nitrate inhibits ammonium uptake, although I'm less confident about this since I have no means of measuring such a phenomenon and since it is extremely difficult to separate an ammonium uptake metric from ammonium attenuation via bacterial nitrification. I assume that if the bacterial colonies are robust then there is no need to worry about NH4 uptake inhibition in plants simply because the bacteria will do the work for you.

Cheers,


----------



## JamesC

I'm going to have another longer term trial of dosing my tank with urea. All plants grow well except for two that look like they are suffering a calcium deficiency. The two are Alternathera Reinekii and Ludwigia Glandulosa which are also the only hard stem type plants I have.

For those interested this is what I plan to dose daily on my 200 litre tank:

3.3g Potassium Nitrate
2.0g Urea
10.0g Potassium Sulphate
0.9g Potassium Phosphate
8.0g Magnesium Sulphate
500ml Water

5ml Tropica TPN equivalent Trace

25ml of the macro solution gives:
0.5ppm NO3
0.5ppm Urea
0.15ppm PO4
1.5ppm K
0.2ppm Mg

Interestingly for me anyway is that both the NO3 and urea nitrogen content is exactly the same as I currently dose which is 1.5ppm NO3.

James


----------



## zig

In case you didn't spot it down the end of that last link he gives another link to his new improved Eudrakon N formula and his reasons why, only launched a few days ago 13/12/08.

http://www.drak.de/en/products/fertilizer/eudrakon-n.html


----------



## GreenNeedle

What I was implying with the last statement in my last post was that there is huge investment in garden ferts research whether just for composts or for ferts such as ours.  Much more than in aquatic ferts.  I would guess the research funding is maybe equal to turnover of aquatic ferts!!!

I also acknowledge that every manufacturer has their different philosophy and aim BUT the one I worked for added KNO3 to its compost and soluble as well as adding the organic element (farm manure in compost's case)

There must be a reason why this manufacturer comes out top in most cases in the 'which' reviews each year (won for the past 8 years!!!.)  There must also be a reason why these people with more funding are using both together.  If it is a case of dilution negates the problem of ammonia versus inorganic why do they use both????  Why not just put more organic in the compost.  It is after all much cheaper!!! 1 ton of farm manure to these companies costs Â£5 whereas 1 ton of KNO3 costs Â£300+ at present rates!!!!

I can see that the KNO3 is much higher concentration per tonne but still is it 60x the concentration???

AC


----------



## ceg4048

zig said:
			
		

> In case you didn't spot it down the end of that last link he gives another link to his new improved Eudrakon N formula and his reasons why, only launched a few days ago 13/12/08.
> 
> http://www.drak.de/en/products/fertilizer/eudrakon-n.html




Thanks Peter, I missed that. So now his new and improved formula has more nitrate? Oh, but wait a minute - he says that nitrate causes algae? Why don't I have algae even though I dose 40ppm per week, 4X his suggested maximum? And why does BGA go away when the nitrate dosing is increased? And he's charging 20 Euros for a liter bottle of this stuff? For 20 Euros at current exchange rate you can buy enough Urea/KNO3 powder from Garden Direct to make 100 home grown liters. I'll be willing to bet the mix that James is using is just as effective as Eudrakon N :? 

Cheers,


----------



## JDowns

JamesC said:
			
		

> I'm going to have another longer term trial of dosing my tank with urea. All plants grow well except for two that look like they are suffering a calcium deficiency. The two are Alternathera Reinekii and Ludwigia Glandulosa which are also the only hard stem type plants I have.



Professional Lurker here.

This reminds me of a paper I read, which I can't seem to find.  Maybe someone here, or Tom, can clarify.   Isn't urea as a form of N preferred when Ca is not abdundant?  When Ca is "non limiting" then NO3 is preferrential.  Couldn't this note why some people have problems with urea as a fertilizer, as Ca levels may play a role in the uptake of the preferrential form of N.   Also are Ca defeciencies more / less pronounced dependant on the predominant N source?   Forgive my vagueness on this since I can't seem to find the paper, but I'm sure at least Clive or Tom may know of the source, or I am remembering completely incorrectly on this.

This also has me thinking about soft water plants (ie Tonina's).  Typically throughout the hobby those that have "harder water" have both a high KH and GH, and soft water vice versa.   Given Tonina's symptoms of yellowing and melting in harder water, mimicing N deficiency, could these soft water plants have a preference to a form of N.


----------



## JamesC

It's been just over two weeks now since I started dosing urea and I have noticed a dramatic change in my Alternathera Reinekii and Ludwigia Glandulosa. Both are now producing much larger and non-crinkled leaves compared to before, which I must admit has surprised me. All other plants are growing exactly the same as before except maybe the Rotala Macrandra which seems to look fuller and healthier. When I last dosed urea I didn't really notice any difference so it may not be the urea which has made the difference. The one thing that is different from last time, is that this time I reduced the nitrate dosing to compensate for the nitrogen content in the urea. Many people have reported that having lower nitrate levels benefit certain stem plants that have hard stems like Alternathera Reinekii and Ludwigia Glandulosa.

Next step is to increase nitrate levels and see how the plants react.

In the mean time I'm really happy with adding urea and plan to continue dosing it for the foreseeable future. There have been no noticeable effects with fish or shrimp and no algae problems either.

James


----------



## George Farmer

Brilliant, James.  Thanks for sharing.


----------



## JamesC

I've been asked to put up a photo of the new growth in the Ludwigia Glandulosa after dosing urea, so here goes.

Before dosing urea






After dosing urea









James


----------



## JamesC

With nearly 3 weeks of increased NO3 dosing the Ludwigia Glandulosa has once again started to grow in with twisted deformed leaves. I have also been dosing urea as before during this period. This would suggest that it is the increased NO3 that is causing the deformations rather than anything to do with the urea preventing it. 

I'm currently reducing NO3 levels again and will carry on with my lean NO3 and urea dosing as before as it seems to work really well for me.

James


----------



## Themuleous

Interesting James, thanks for keeping us posted.  The difference in growth is quite marked.

Sam


----------



## JamesC

Yeah, it's quite amazing. I don't have any pictures of when it gets really bad. The first picture above is actually no where near as bad as it gets sometimes. I always suspected CO2 but the plant is in direct line with my filter outlet which is where my CO2 reactor is. This means it gets a great flow across the whole of the plant which is rich in CO2.

Still not sure what really is going on as some people manage to grow it fine in high NO3 enviroments whilst others just cannot. All part of the great mystery.

James


----------



## JanOve

JamesC said:
			
		

> Yeah, it's quite amazing. I don't have any pictures of when it gets really bad. The first picture above is actually no where near as bad as it gets sometimes. I always suspected CO2 but the plant is in direct line with my filter outlet which is where my CO2 reactor is. This means it gets a great flow across the whole of the plant which is rich in CO2.
> 
> Still not sure what really is going on as some people manage to grow it fine in high NO3 enviroments whilst others just cannot. All part of the great mystery.
> 
> James


 I had similar issues with Althernanthera reineckii in a 300l, but in a nano (25l) the stunting disappeared.
Both tanks dosed EI and with high light, the large tank lit with 4x39w T5 and the small with 70w Hqi.
In my opinion it had to be Co2 related due too more efficient diffusion in the small tank.
I have soft water aswell which might aggravate the stunting.


----------



## ceg4048

Hi James,
             A couple of variables we should be careful when interpreting is that CO2 demand changes as the height of the plant changes simply due to leaf proximity to the light. Low growing L. glandulosa almost always has a clean undistorted leaf structure: 

Here is an example of a specimen grown under extremely high NO3 load (60PPM). At this point the stem was only 4-6 inches tall in a 24 inch deep tank.





However as the stem nears the surface, the effects of the inverse square energy properties of the light will become more pronounced such that even though it may be closer to the CO2, it's also much closer to the light. This is the same specimen after it approximately doubled in height and under the same NO3 dosing regime. While some leaves are still clean others are starting to distort:





At nearly 22 inches tall the top leaves of this this specimen is only a few inches from, and is directly under  a 55 watt T5 bulb ans is directly within the flow path of the spraybar, yet, these leaves are distorted. A similar phenomenon has affected an L. mullerti in the background. The lower leaves are much less distorted than the ones on top.





I'm much more inclined to believe that there are CO2 assimilation limitations due to physiology in some plants rather than nitrogen assimilation issues. The fact that the other plants in the tank have not demonstrated any growth pattern changes supports this.

Also, have you been monitoring the nitrate levels in the tank while dosing urea? It's still unclear what the bacterial response to increased ammonia levels are. Barr noted that urease and bacterial response to elevated urea levels is high so there is a strong possibility that higher populations may actually be converting the urea to nitrate.

Cheers,


----------



## JamesC

Very interesting Clive. I initially thought it must be CO2 and have tried various experiments with CO2 but to no avail. Dosing lower NO3 made a big impact though, but why it does I don't know.

Also what role the urea plays I don't know either as I'm afraid I haven't been testing NO3 levels. If all the urea was converted to NO3 then theoretically NO3 levels should be exactly the same as when I dosed just NO3 as the total Nitrogen added is the same.

James


----------



## plantbrain

Urea is pretty cheap  
Just be careful with higher light and poor CO2/low pant biomass.
Low or varied CO2 will stunt tips.
You can see this in natural systems as the plant biomass and the competition for CO2 increases as the plants fill in during the growing season. Tips get progressively smaller, even though N and P are not limiting(plenty in the sediments).
This is why plants, particularly the weedy aquatics started to use bicarbonate. This is huge advantage.

How you dose at lower levels can influence CO2 demand a great deal in some species, but not others.
Not all plants have the same CO2 deamnd and ability to sequester CO2.

CO2 is 40-45% of the plant biomass as C.
So you will see the most dramatic issues, both algae and growth forms, with CO2 than anything else.

That's why 95% of the issues are CO2 related.
It changes fast, within 1 hour if can go from 30ppm to 3ppm.

Can N, P or any other nutrient change that fast?

Urea BTW rapidly changes to NO3 in water/aquatic systems.
Try NH4Cl, (NH4)2SO4 etc if you are interested in reduced forms of N.



Regards, 
Tom barr


----------



## plantbrain

Here's some no#'s for Urea to NH4 transformation:

http://www.springerlink.com/content/m761n307t70t5p07/

Seems that sediment and filters do a lot, perhaps much more than plants.
You basically are growing more bacterial filtration by slowly adding more and more Urea or NH4.
Unless you have a system where there is no sediment or bacteria, the NH4 will be converted and used mostly by the bacteria.

Why do new aquariums get algae more often?
Bacteria(lack of) mostly.................

That's what is different between the systems(old vs new) as well as total biomass of plants.

Regards, 
Tom Barr


----------



## JamesC

I agree totally Tom. I thought for ages it was CO2 and even went to the trouble of putting a diffuser in the tank so the water flow covered the plants in micro bubbles all day. They still wouldn't grow properly. I tried for ages changing CO2 methods and flow but couldn't ever make a certain group of plants grow well. This is why I started looking elsewhere for an answer. The first time I tried the urea dosing I kept the NO3 dosing the same which is why I didn't notice any difference. This last time I reduced the the NO3 dosing right back when I dosed the urea.

I can only comment on what I see in my tank and low NO3 dosing seems to work for me. This isn't to say that CO2 hasn't got something to do with it but I think that my fish are getting a bit fed up with me whilst I'm pushing CO2 levels high. I know I'm not alone with these problems either. I just wish I had more time and money to do some more testing.

The results are quite staggering and very quick to take affect. Here is a stem of rotala rotudifolia that was initial subjected to low NO3 and urea dosing. Then I upped the NO3 and stopped the urea dosing for a while. Then I returned to low NO3 and urea dosing again. It's fairly easy to see where I made the changes.





James


----------



## George Farmer

Amazing, James.

Thanks for sharing, as always.


----------



## Themuleous

Yeh really interesting, cheers James.

Sam


----------



## Themuleous

plantbrain said:
			
		

> Urea is pretty cheap  Urea BTW rapidly changes to NO3 in water/aquatic systems.



If this is the case, whats the advantage of using urea over KNO3?

Sam


----------



## JamesC

Urea hydolyses to ammonia and carbon dioxide. Bacteria then convert to NO2 then NO3.

I'm presuming that the plants use the urea or ammonia before the bacteria.

James


----------



## Themuleous

Right, worth a try then!

Sam


----------



## plantbrain

JamesC said:
			
		

> Urea hydolyses to ammonia and carbon dioxide. Bacteria then convert to NO2 then NO3.
> 
> I'm presuming that the plants use the urea or ammonia before the bacteria.
> 
> James



So.............let's turn this question and observation around, why don't my tankjs and plants, as well as others, not have this stunting issue?

Answer me that. :idea: 

Then you can say something.
Low NO3 and high NO3, it does take a little time, about a week or so, for the plants to adapt to highe rlevels of NO3, but this should be an issue.

I know something else is occurring because I simply do not have this issue nor have had it.
I keep Tonias, erios and then the easy to grow plants like those in the last couple of pictures.
I add 20-30ppm of NO3 via KNO3 and also have higher fish loads, that are well fed.

Why dose Urea when you can have fish?
I've done tanks without fish also, but had even better results.
This includes the Erios and Tonias etc, so called "sensitive" plants. 

When everyone claimed that PO4 caused algae, I also knew they could not be right using the exact same logic I am here.
If what you suggest is true, then why does it not occur in my tanks nor has for what? 15 years or so now?

Where's the stunting and dramatic changes?

I don't see it.

I know that this idea about NO3 stunting plants is poppycock.
You need to look elsewhere and run the dosing longer than  week, typically 3 weeks is a good amount.

You also have no control in your test, only an issue  
Until you have a control, folks still think that high PO4 = algae blooms.

When they see the tanks with high PO4 and no algae, then they know it's not PO4.
Same thing here, I have tanks, as do many others, with higher NO3, and no stunting.
Some folks using less PO4 found that they had less algae, not from the limitation of algae, rather,m the secondary effects of limiting PO4, so that the plants used less CO2. If they added non limiting PO4, then they shifted to limiting CO2.

So they assumed it was PO4, not some other factor that was suppose to be independent(CO2, maybe NO3 etc). You have the same issue here. I know you do. 

I do not know why your plants are stunting, you do not either, only that what you are doing causes good growth if you add urea. I can only rule out things one step at a time, but I already did that a decade ago here...................

And since have confirmed it a thousand times over.

As folks fiddle with nutrients more and more, they have progressively trouble managing them and keeping tabs on CO2.
While CO2 is not a simple issue, adding more till your fish gasp is not what I've suggested to anyone. Current, surface movement, mist, light intensity, flow rates through the tank etc and method of measuring the CO2 all make a large difference.
ed
Measuring light also can help compare things with other folks.

Maybe it's CO2, maybe it's something in the tap, maybe it's bacteria. Unless you bother to rule things out, you honestly cannot say, I cannot either. I can only be certain that high NO3, in and other itself is not the issue.
Then I can go back and look at other alternatives. Unless you can confirm and rule things out, provide controls etc, you really cannot answer much. That issue goes way back, even really smart folks that know/knew better gloss over that.

It's fine to insist that you are right, but when I have these same plants and have 30ppm of NO3? Add high NO3, have no issues for many years.......I really cannot buy the logic. I do not dispute the observations , but that does nothing to explain why my tanks have no such issues nor others.

So it cannot be NO3 in and of itself.
there's some other issues occurring.

BTW, I have these same plants in my tanks right now.
They look mighty healthy and get trimmed often.

How can you explain those observations?


Regards, 
Tom Barr


----------



## spider72

Hi guys

I have found quite intersting article, related to this subject.
http://www.apms.org/japm/vol19/v19p40.pdf

Regards


----------



## Sumo

JamesC said:
			
		

> I agree totally Tom. I thought for ages it was CO2 and even went to the trouble of putting a diffuser in the tank so the water flow covered the plants in micro bubbles all day. They still wouldn't grow properly. I tried for ages changing CO2 methods and flow but couldn't ever make a certain group of plants grow well. This is why I started looking elsewhere for an answer. The first time I tried the urea dosing I kept the NO3 dosing the same which is why I didn't notice any difference. This last time I reduced the the NO3 dosing right back when I dosed the urea.
> 
> I can only comment on what I see in my tank and low NO3 dosing seems to work for me. This isn't to say that CO2 hasn't got something to do with it but I think that my fish are getting a bit fed up with me whilst I'm pushing CO2 levels high. I know I'm not alone with these problems either. I just wish I had more time and money to do some more testing.
> 
> The results are quite staggering and very quick to take affect. Here is a stem of rotala rotudifolia that was initial subjected to low NO3 and urea dosing. Then I upped the NO3 and stopped the urea dosing for a while. Then I returned to low NO3 and urea dosing again. It's fairly easy to see where I made the changes.
> 
> 
> 
> 
> 
> 
> James



Boron deficiency seems.
Best regards


----------



## JamesC

Just to update this thread a bit. I'm still dosing my tank with urea and seeing no problems whatsoever with it. I'm always curious to see what commercial products use and have just seen today that the Pfertz line use Potassium Nitrate and Urea in their Nitrogen dosing solution. Pfertz are very popular in the US and come highly recommended by many people.

It appears that most of the major dosing systems use either ammonium or urea as a partial source of nitrogen in their solutions. They also use potassium nitrate as well. The list so far includes ADA, Seachem, Tropica and Pfertz. Also other specialised producers like Drak use urea, ammonium and nitrate in their Eudrakon N product. This is popular in Europe.

You may argue that the amounts may be small, but if that's the case why bother adding them at all then? I know some people will say that they just use potassium nitrate and have perfectly healthy tanks and that adding urea is pointless and risking algae, but I have seen a definite improvement in some of my plants.

If you do large water changes because you believe it lowers the ammonia levels to help prevent algae and then dose any of the above products straight afterwards you will be adding much more ammonium/urea back in than you could have possibly removed. Food for thought!!

James


----------



## Dave Spencer

Well, if you are seeing an improvement James, I am definitely going to consider giving it a try. 

Dave.


----------



## JamesC

You do need to be more careful than when just dosing nitrate and be careful not to overdose. There have been many people who have decided to overdose TPN+ and then got into problems as ammonium levels have gone quite high. 

James


----------



## plantbrain

JamesC said:
			
		

> Just to update this thread a bit. I'm still dosing my tank with urea and seeing no problems whatsoever with it. I'm always curious to see what commercial products use and have just seen today that the Pfertz line use Potassium Nitrate and Urea in their Nitrogen dosing solution. Pfertz are very popular in the US and come highly recommended by many people.
> 
> It appears that most of the major dosing systems use either ammonium or urea as a partial source of nitrogen in their solutions. They also use potassium nitrate as well. The list so far includes ADA, Seachem, Tropica and Pfertz. Also other specialised producers like Drak use urea, ammonium and nitrate in their Eudrakon N product. This is popular in Europe.
> 
> You may argue that the amounts may be small, but if that's the case why bother adding them at all then? I know some people will say that they just use potassium nitrate and have perfectly healthy tanks and that adding urea is pointless and risking algae, but I have seen a definite improvement in some of my plants.
> 
> If you do large water changes because you believe it lowers the ammonia levels to help prevent algae and then dose any of the above products straight afterwards you will be adding much more ammonium/urea back in than you could have possibly removed. Food for thought!!
> 
> James



I think the argument is that "some" NH4 is better than "none".
It's long been known that adding a mix of NH4 and NO3 produces the highest yields in most plants, some prefer a but more of one ratio over the other, but by and large, this is not new.

I think some have taken some of what I've said in the past about NH4 and algae a bit too far.
I know if you dose a high amount to a high light tank, I can induce algae repeatedly.
But this is only green water.

With high fish loads, eg, overloading the fish tank with high light, I was also able to do the same.
This followed with Reds and finally green algae blooms in a successional bloom over time.

We do not know what the light intensity is here. Nor the dosing rates, nor how long the dosing rates and how they where added. a mature tank should be able to withstand a decent addition of some more fish, or .....NH4 loading.
Much like fish less cycling, once the bacteria have had time, they can convert the NH4 to NO3 even without plants..........

So dosing a small amount really has less effect, if all is going well for CO2/stable light etc, if not, then this can back up and you end up with algae more than without any source of NH4(fish or from inorganic sources etc)

Now I'm of the philosophy coming at this from a fish hobbyists, which supplies all the NH4 I might need.
I like fish and is why I keep aquariums.
Plants are in many respects, a secondary hobby.
Like slowly adjusting the stocking levels, adding NH4 to a fish tank that has been fishless cycled, is the same as adding the Urea or NH4CL or (NH4)2SO4 or whatever form of salt for NH4.
Are the plants really getting the this slug dose of NH4?
Or is a lot of it going to bacteria and ending up as NO3 in the end?

Plants do best with a mixture of NH4 and NO3. Not one or the other............(which is where a lot of debates foolishly end up) Now fish cannot supply all the NO3 I might need, since it all starts off as NH4, but they can supply plenty of NH4.
They also supply it metered, slowly and continuously at lower residual dosage than most even the best dosing pumps might.

So if you have fish, there's ample NH4 dosing right there.
Top it off with KNO3...........

Seems like the best management and the least risk to me given the choices/trade offs.

Adding NH4 to commercial mixtures is done for a couple of reasons, it's cheap, it's also often used at low ppm's for hydroponic fertigation, too much NH4 ends up burning terrestrial leaves and mist grow out systems.
This is the same for ornamental plants for landscapes as it is for aquatic plants, they are grown in very similar fashions commercially.

Virtually all aquatics like some NH4 and NO3, they serve different and similar roles, NO3 is the main anion inside the tonoplast which helps to drive growth, turgor pressure and ionic balance, NH4 is the easier form of N to assimilate into amino acids, but NO3 is a better long term supply and can be dosed at high rates with less loss due to bacteria transformations etc. 

Rather than the thinking of either/or, using both works well.
 If you lack fish, then adding it is likely wise(an option), but otherwise, simply feed fish well and have decent stocking level.

James, what is your stocking levels and what types of fish food and frequency do you feed?

I'm loaded with 0.5 Amano shrimp per gal, 0.5" of plecos/catfish, then 1 per gal of tetras/schooling fish.
I'm feeding 3x a day, flake,. sticks and a mix of bloodworm, mysis, brine 2x a day.

That's a fair amount of NH4 coming in, with the assumption of 10% retention in the fish per N added via from fish food.

Adding a small amount, you can go to 0.8ppm per day of NH4 without issues I think, without any fish, should result in improved plant growth I would predict. If you add too much light, mess up CO2, then the chances of messing the system are higher, but that assumes dependence, not independent results with NH4 in and of itself. It also assumes that fish and shrimp are not adversely affected by inorganic dosing of NH4. 
Food comes in bound, then is excreated slowly to urea/NH4.
So the total exposure is much less.
Still, in a well run planted tank, the dosage should not cause harm, it's when poor management occurs, then the NH4 could be toxic, much more so than NO3.

I'm not so sure you get that much out of the NH4 dosing really.
I've had tanks do extremely well with no fish and no NH4 dosing or snails or any other smaller criters as a source of NH4.
Just dosed NO3 as the sole source, grew Erios, every sort of picky stem plant etc.

No issues at all.

But.........I like fish, so they are in all my aquariums.
Still, I think some misconceptions have come about with some things I've said regarding algae and NH4.

Dose makes the poison, not complete absense/presence.
I have plenty of NH4 in my tanks, but in a different form/method: fish. These tanks also will go downhill much easier than a tank without fish/ withoutNH4 dosing also. So the dependence on other factors like CO2/lighting are no different than inorganic dosing of urea/NH4.


Regards, 
Tom Barr


----------



## emreutku

Hi james, i read your write-ups and Ä° like very much, also i like brilliant ceg4048 and mr. Tom Barr as always.
I want to ask does 0,5ppm NO3 and 0,5ppm urea add the same amount of nitrogen to the tank?

I read the seachem nitrogen (derived from potassium nitrate and urea), 
http://www.seachem.com/Products/product ... rogen.html

""
According to seachem;
One-half of the nitrogen in Flourish Nitrogenâ„¢ is from nitrate so you can get a reasonable estimate of nitrogen levels by doubling a nitrate reading...

Direction;
To target a specific nitrogen increase, dose according to the following formula: 0.25vn=m, where v= volume of tank in gallons*, n=desired nitrogen increase (if using a â€œnitrate equivalentâ€ value for â€œnâ€ then use a factor of 0.05 instead of 0.25 in the formula) and m=volume of product to use in mL. For example to raise 20 gallons* by 0.20 mg/L nitrogen you would use: 0.25*20*0.20=1 mL. ""

what does it means?

****

In Turkey there is available a very cheap product among the others called " mircobe-lift bloom and grow"
This product contains %10 urea, no phosphate and and contains other micronutrients also.
Can we use Ä±t in out high tech planted tanks?

thanks and regards


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## plantbrain

No, they do not add the same amount, it depends on the measurement units used, N as Urea or N and NH4, are different since you need to other parts of those ions.

You should be able to use that product without issue in Turkey.
I think using NH4 via the sediment is the way to go, after that, fish waste, finally, dosing it via a solution.

All work, but sediments add a much higher % and that are non toxic but still available to plants.
This last only about a year, so fish waste is good as well, water column needs dosed at smaller % and lot can be removed via bacteria transformation. I do not think aquarist get that much out of urea vs NO3 in % growth in the water column.

If KNO3 is too tough to find, or urea is cheaper and available, not really an issue, problem is that over the years, folks have gotten really wild with KNO3, I would not suggest wide spread use except in very small amounts for planted aquarist, they will lard it on and kill fish and burn things.

Commercial liquid aquarium products are very very dilute, mostly water, with a tiny bit of ferts added, so the % NH4 is still pretty small, the sediment holds roughly 20-2000X more NH4.

I think adding say 1:3 ratio as far N from NO3 vs NH4(as N, not ions) is fine in most solutions.
So say a 10ppm of NO3 and say .7 ppm of NH4 per dose is the upper limits.
You might be able to cut this in 1/2, say 5ppm and .4ppm of NH4 if you did this once every other day on a moderately lit tank and get good results.

I like sediments as the source though.

Regards, 
Tom Barr


Regards, 
Tom Barr


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## GHNelson

Very interesting subject
hoggie


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## dw1305

Hi all,





hogan53 said:


> Very interesting subject


Thanks for this. I've never read this thread before, and it is really interesting.

cheers Darrel


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## snobi

plantbrain said:


> Regards,
> Tom Barr


regards to everyone, btw tom haven't you tested it yourself using UREA as for test? and see the difference with the other one?, i don't have a budget to try out the test but i will give it a shot since it was cheap here in the Philippines (KNO3 is hard to come by + plantex csm+b is also hard to find and badluck nothing at all.), i also post a question of how much urea is safe to dose, 

I'm going to test this 0.5ppm to my 50gallon tank and see a different in 3 to 4 weeks.

regards,
Roy


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## micheljq

Hello, very interesting thread,

If dosing UREA gives this reaction : CO(NH2)2 + H2O + urease -> 2NH3 +CO2

Does it mean we could use it to dose carbon (co2), instead of the pressurised co2 systems?  CO2 is not cheap here.  I see an interest because it brings co2 in the tank.  However i am fearful of the NH3 it creates.  I might as well dose UREA and stop using my co2 cylinder..  but i fear for my little fishes.

Michel.


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## dw1305

Hi all, 





micheljq said:


> Does it mean we could use it to dose carbon (co2), instead of the pressurised co2 systems?


No. 





micheljq said:


> However i am fearful of the NH3 it creates


Yes that is the one, toxic amounts of NH3 long before you get to appreciable amounts of CO2.

One of the original ideas behind soil substrate tanks was that the break down of organic matter would supply CO2 to the plants, and this was one reason for having limited water movement. Problems come because the decomposition processes deplete oxygen.

I'm not a CO2 (or carbon supplement user) but is "liquid carbon" (glutaraldehyde based) an option?

cheers Darrel


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## Manuel Arias

dw1305 said:


> I'm not a CO2 (or carbon supplement user) but is "liquid carbon" (glutaraldehyde based) an option?



Within the time, and more and more convinced that glutaraldehyde based products are just a complement of normal CO2 injection. Some plants that are very bad to uptake HCO3- or CO2 dissolved in water can benefit of this. But I strongly doubt that products like Exel  can replace CO2 injection. I see more a synergy than a replacement strategy with them.

Cheers,

Manuel


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## zozo

I've used little bit of regular 2-2-4 fertilizer you would use for garden or potted plants for a while in the tank to supplement the tropica dose a bit extra with N. 1 week Tropica the other week the 2-2-4. It contained 0.5 % - NH4 and 2% - NO3.. Had medium light at the time and very rappidly a nice green carpet of alga attaching to the substrate. Which went away again after stopping it and reducing the light..  Only a little bit like every other week 2ml on 100 litre was enough or maybe to much.  Nasty stuff.

Now i'm dosing KNO3 with KH2PO4 and back to former light schedule, plants do beter and it seems to reduce algae growth.


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## oviparous

Been dosing urea, daily, for some years, and i'm  glad i once started it. 
Some plant react very good (better colour, bigger leafs), others don't seem to care.
I'm now dosing 2 x 0,25 mg/l a day, hoping the urea will last longer before being processed by bacteria 
than 1 dose of 0,5 mg/l.



> If dosing UREA gives this reaction : CO(NH2)2 + H2O + urease -> 2NH3 +CO2
> 
> Does it mean we could use it to dose carbon (co2), instead of the pressurised co2 systems?..
> I see an interest because it brings co2 in the tank.


The impact of it if processed by bacteria  would be, like Darrel pointed out, practically none.
But i am curious how a plant uses the CO2 when urea is taken up by the plant, and processed inside the plant. Would the CO2  be transported to the Calvin cycle,  used in another way or dumped out of the plant?


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## Manuel Arias

oviparous said:


> But i am curious how a plant uses the CO2 when urea is taken up by the plant, and processed inside the plant. Would the CO2 be transported to the Calvin cycle, used in another way or dumped out of the plant?



This is a hard question. Thinking about the plant metabolism, I would say that anabolism of urea to retrieve ammonium happens at a different point than photosynthesis. For instance, photosynthesis fixes the carbon but this is partially burnt to produce energy that also generates CO2. That energy is then employed for other catabolic reactions, like assimilating nitrogen to form amino-acids and then proteins. The process with urea seems to be not different from what happens during breathing, so CO2 generated at such point will be more likely released to water.

There is, however, an exception. Some aquatic plants have an adaptation in order to improve CO2 absorption for photosynthesis, which is called aerenchymas (see photo below). These are mainly (but not only) thin tubes running all along the plant, some times connecting even leaves and roots. These aerenchyma are empty space, with no water, but filled with gases. These gases are mainly oxygen and CO2, which comes from the plant activities and, in some cases, because the plants use this to absorb CO2 at root level and transport it to the leaves where the photosynthesis happens. In this occasion, plant is actually pumping the byproducts of its metabolism (both CO2 and oxygen) to these spaces so they can recycle it. Obviously this is just a part of the whole volume of gases being generated, but it is a good contribution in many species. These aerenchyma are the source of bubbles some people observe when trimming some plants (e.g. _Eleocharis acicularis_). A secondary function of the aerenchymas are to add buoyancy to the plant, helping to keep the tails straight towards water surface and then allowing thew plant to need less structural molecules to keep the plant in position. The weight of this part, however, it is very specific for each species.

Cheers,

Manuel


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## roadmaster

Photo look's like my arteries according to the Doctor.
Two heart attack's and four stent's, and I'm still among those above ground.


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## mlportersr

An important point to remember is that while in general plants metabolize ammonia, some plants (mainly Monocots, I believe) have evolved to prefer nitrates.

Sent from my P022 using Tapatalk


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## Zeus.

Old thread but great read 

Bookmarked for future reference


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