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Dosing with Ammonia and Urea

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 £5 whereas 1 ton of KNO3 costs £300+ at present rates!!!!

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

AC
 
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
Click to expand...


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,
 
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.
Click to expand...

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.
 
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
 
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
LudwigiaGlandulosaBefore01.jpg


After dosing urea
LudwigiaGlandulosaAfter01.jpg

LudwigiaGlandulosaAfter02.jpg


James
 
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
 
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
 
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
Click to expand...
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.
 
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.
2493684850038170470S600x600Q85.jpg


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:
2684078270038170470S600x600Q85.jpg


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.
2367016030038170470S600x600Q85.jpg


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,
 
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
 
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
 
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
 
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.

RotalaRotundifoliaDeformation.jpg

James
 
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
 
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