Olympus is Calling.

jaypeecee

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Honestly you can't conclude that.
Hi Darrel,

It's neither what I expected nor what I had wanted to be the outcome. That's why I invite others to repeat the experiment - perhaps with faster-growing plants. Then, I guess the end result may well be different.
...it is almost impossible to get a microbe free system, even in the lab

And that is what my experiment demonstrates.

JPC
 

jaypeecee

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Because they are epiphytes? Duckweed (Lemna minor) would be more suitable, just because of its faster growth rate and aerial advantage. It would also get around any complexity offered by root/substrate interactions.
Hi Darrel,

I forgot to mention that there was no substrate in my setup.

JPC
 

dw1305

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Hi all,
It's neither what I expected nor what I had wanted to be the outcome. That's why I invite others to repeat the experiment - perhaps with faster-growing plants. Then, I guess the end result may well be different.
I honestly don't know what happened to the ammonia you had added. It may have undergone nitrification etc. , but there are all sorts of questions. Did you start with RO water? If you did? What other nutrients did you add to it? etc.

If a study has been published as a peer reviewed scientific paper, then it is likely to be much more accurate and much more rigorous than anything that I could accomplish.

It is a bit like the <"Archaea papers">, I can't independently verify them, if you like it is a "faith position", based on a faith on the <"scientific method">.

cheers Darrel
 
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jaypeecee

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Hi @dw1305

I am in little doubt that the ammonia had undergone nitrification. Hence the measurable nitrite and nitrate after a few days. I used remineralized rainwater. Conductivity was ~200microS/cm. To this I added 0.3 ml of Flourish Fe, 0.4 ml of Flourish P and 0.8 ml of Flourish Trace. Alkalinity was 2.5 dKH and General Hardness was 3.5 dGH. I didn't measure pH as my pH probe was out of action.
If a study has been published as a peer reviewed scientific paper, then it is likely to be much more accurate and much more rigorous than anything that I could accomplish.
As a (retired!) scientist myself, I always refer to peer-reviewed papers, when available (and preferably free). That's why my Dropbox is bursting at the seams with them! But, the research that has been carried out on ammonium uptake by plants doesn't invalidate my results, or does it? OK, I don't have thousands of pounds of analytical equipment but it's not necessary to measure TAN, NO2- and NO3- to +/- 2% accuracy in the experiment that I have conducted.

In short, I would like to repeat this experiment sometime using fast-growing plants. Unfortunately, I am unable to nip out to my local MA during the current pandemic. And I haven't seen any members of the local aquarist society since February of this year - so I can't nab some plants from them. I also have in mind including Urea in the ferts mixture. Like yourself, I hadn't realized how non-toxic this is to fish.

JPC
 

dw1305

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Hi all,
But, the research that has been carried out on ammonium uptake by plants doesn't invalidate my results, or does it?
No, it definitely doesn't invalidate your result, whatever happens you have contributed to the sum of human knowledge. If people try similar experiments, and come up with similar results, then we know that our present view of ammonia uptake in plant/microbe systems isn't right.
As a (retired!) scientist myself,
I am in little doubt that the ammonia had undergone nitrification.
But that is really the point, I'm <"always in doubt, about pretty much everything">. I'm not saying that you are right or wrong, but I don't think that you can conclude all that scientific work, on phytoremediation and ammonia uptake is wrong, based on your experiment. Have a look at <"Ammonium and Nitrate Uptake by the Floating Plant Landoltia punctata">.

As a wider point, from my point of view I don't really care where, why or how nitrification takes place, as long as <"ammonia and nitrite are removed from the aquarium rapidly"> and efficiently I'm not that bothered, what the process is. If you like, it's more the <"destination that interests me">, rather than the journey.

I'd really like to be able to quantify all the processes that are occurring in the aquarium, but I'm not sure it is an achievable aim.

cheers Darrel
 

jaypeecee

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...I don't think that you can conclude all that scientific work, on phytoremediation and ammonia uptake is wrong, based on your experiment. Have a look at <"Ammonium and Nitrate Uptake by the Floating Plant Landoltia punctata">.
Hi Darrel

Oh, I didn't mean to dismiss the scientific work carried out on phytoremediation and ammonia. Sorry if I gave that impression. No, no, thrice no! I bow down to their superior knowledge and research excellence. I just did a simple experiment and made a few measurements. I wasn't expecting to detect any nitrite or nitrate. In my naivety, I was expecting the plants to gobble up the ammonium but that didn't happen.

I will check out the paper you referenced. In fact, I think I already have a copy.

JPC
 

dw1305

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Hi all,
In an attempt to eliminate nitrifying bacteria, archaea, etc., I sterilized everything in the tank - glass panels, driftwood, plants, etc. using potassium permanganate. I even ran a UV-C sterilizer at this stage to kill off any bacteria in the water column. Then, using ammonium chloride, I raised the tank TAN (NH4 + NH3) to 1 - 1.5 mg/l (ppm). After three days, I re-measured TAN + nitrite + nitrate. Then, calculated the nitrogen ppm at the beginning and end of the experiment. Conclusion: No significant nitrogen had been taken up by the plants. Instead, despite my attempts to eliminate nitrification, it was clear that the ammonia had been oxidized to nitrite and then to nitrate!
I just did a simple experiment and made a few measurements. I wasn't expecting to detect any nitrite or nitrate. In my naivety, I was expecting the plants to gobble up the ammonium but that didn't happen.
What was the nitrate measurement at the end of the experiment (or the combined NO2 + NO3 levels)? I can't see a mechanism for nitrification, but that doesn't mean that I'm not missing something.

cheers Darrel
 

jaypeecee

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What was the nitrate measurement at the end of the experiment (or the combined NO2 + NO3 levels)? I can't see a mechanism for nitrification, but that doesn't mean that I'm not missing something.
Good afternoon, Darrel

The nitrate figure at the end of the experiment was 5 - 15 ppm, nitrite was 1 ppm. Starting ammonia (TAN) was 1 - 1.5 ppm and remaining ammonia (TAN) was 0.4 ppm. And this took place over just 28 hours at 24C water temperature. The tank was illuminated during the day. When I totted up the nitrogen concentrations before and after the experiment, the plants didn't appear to have taken up any of the nitrogen compounds. BTW, what did you mean by "I can't see a mechanism for nitrification"? Doesn't it just suggest that there were sufficient nitrifying bacteria and/or Archaea in the tank throughout the experiment?

Finally, I must apologize to @Zeus. , the OP of this thread for this detour.

JPC
 

dw1305

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Hi all,
Afternoon John, my apologies to Karl as well.
The nitrate figure at the end of the experiment was 5 - 15 ppm, nitrite was 1 ppm. Starting ammonia (TAN) was 1 - 1.5 ppm and remaining ammonia (TAN) was 0.4 ppm.
Curiouser and curiouser. I don't know if @alto has any thoughts?

Could you try it again at without remineralizing the rain-water? I might add a dash of white vinegar (or Vit C./Citric acid) as well, that should ensure the pH is below pH7 and all the TAN is plant available as ammonium ions (NH4+). It should also <"inhibit traditional nitrifiers"> (although possibly not all the Archaea).

From <"EPA - Nitrification"> we have:

NH3 + O2 → NO2 - + 3H+ + 2e-
NO2 - + H2O → NO3 - + 2H+ +2e-

That shows that it is a conversion of one molecule of NH3 to one molecule of NO3 and that we can ignore RMM and % N etc.

We've ended up with a lot more nitrogen than we started with? So the source of the extra nitrate must be the plants? I can imagine there might have been some cell damage from the potassium permanganate (KMnO₄) treatment, and a leakage of protein rich chlorophyll etc.
Doesn't it just suggest that there were sufficient nitrifying bacteria and/or Archaea in the tank throughout the experiment?
It does, but assuming that your sterilization worked, where did they come from, from the rain-water? Nothing suggests that they can re-colonize anything like that quickly. Could you boil the rainwater before use?

cheers Darrel
 

Witcher

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Then, calculated the nitrogen ppm at the beginning and end of the experiment. Conclusion: No significant nitrogen had been taken up by the plants.
Hey @jaypeecee for how long did you conducted that experiment? Were the water conditions in original tank (where the plants were coming from) identical with the test tank? And if not, did your plants had a chance to re-program their enzymes to different conditions (which in the effect could delay or stop N intake for some time)?

The nitrate figure at the end of the experiment was 5 - 15 ppm
10ppm in "unknown" area seems to be quite a lot, what Nitrate test you've been using for that?
 

jaypeecee

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Hi Darrel,

Thanks very much for your valued observations and comments. Here are my initial thoughts:

Could you try it again at without remineralizing the rain-water?
Yes, that is certainly possible. What would the advantage of that be?
I might add a dash of white vinegar (or Vit C./Citric acid) as well, that should ensure the pH is below pH7 and all the TAN is plant available as ammonium ions (NH4+).
Yes, good point. I was very annoyed being unable to use my pH meter.
It should also <"inhibit traditional nitrifiers"> (although possibly not all the Archaea).
That would mean a pH in the range 5 - 5.5. Agreed?
That shows that it is a conversion of one molecule of NH3 to one molecule of NO3 and that we can ignore RMM and % N etc.
Yes, that makes things much simpler.
We've ended up with a lot more nitrogen than we started with?
Yes, particularly if the nitrate was more like 15 ppm, instead of 5 ppm.
It does, but assuming that your sterilization worked, where did they come from, from the rain-water? Nothing suggests that they can re-colonize anything like that quickly.
Yes, agreed. I may just cycle the tank water through the UV-C sterilizer for 24 hours beforehand. It's easier than boiling 12 litres of water. Unfortunately, I can't be sure that my attempt at sterilizing with KMnO4 was 100% effective.

JPC
 

dw1305

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Hi all,
Yes, that is certainly possible. What would the advantage of that be?
That would mean a pH in the range 5 - 5.5. Agreed?
Yes just to keep the pH below pH7 and make sure all the TAN was as NH4+, it would stop it degassing and it would ensure that the ammonium ion was plant available. The other advantage would be that it may limit microbial nitrification, even if some microbes survived the initial treatment,

cheers Darrel
 

jaypeecee

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Hi Everyone,

The reason I did this experiment? I got quite excited at the prospect of running a tank without a biological filter*. As this is churning out nitrate, which the plants don't really want (preferring ammonium), it got me thinking. If the plants prefer ammonium, isn't this what we should provide for them? But, what about the fish? They're not going to be happy with ammonium if the water pH is much above 7.5 at which point the ammonium (NH4+) is converted to free, toxic ammonia gas (NH3).

And I'm still thinking but I'm wondering if the use of urea is one possible solution? At which point, I'm leaning on @dw1305, @alto, @zozo, and everyone else for their thoughts.

* i.e. an actual physical piece of equipment

JPC
 

dw1305

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Hi all,
I got quite excited at the prospect of running a tank without a biological filter
Have a look at @Bart Hazes <"posts">.
And I'm still thinking but I'm wondering if the use of urea is one possible solution?
The "Miracle-Gro", (from the <"It's very Green thread">), perks the plants up pretty instantly. <"I guess it is the urea"> content, but I don't actually know.
Looking at the ingredient list, it looks pretty good, especially for a <"relatively cheap product"> (if the link stops working that was less than £5 for a kilogram).

Ingredients: Total Nitrogen (N) (24%) (Ammoniacal Nitrogen (3.5%), Urea Nitrogen (20.5%), Available Phosphate (P2O5) (8%), Soluble Potash (K2O) (16%), Boron (B) (0.02%), Copper (Cu) (0.07%), Water Soluble Copper (Cu) (0.07%), Iron (Fe) (0.15%), Chelated Iron (Fe) (0.15%), Magnesium (Mn) (0.05%), Chelated Manganese (Mn) (0.05%), Molybdenum (Mo) (0.0005%), Zinc (Zn) (0.06%), Water Soluble Zinc (Zn) (0.06%).
Derived from Ammonium Sulfate, Potassium Phosphate, Potassium Chloride, Urea, Urea Phosphate, Boric Acid, Copper Sulfate, Iron EDTA, Manganese EDTA, Sodium Molybdate, and Zinc Sulfate.
Other than not being suitable for aquariums because of the urea/ammonium the only thing "wrong" would be the low magnesium content, which could be very easily rectified by adding some (equally cheap) "Epsom Salts".

cheers Darrel
 
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Zeus.

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Ran the maths and for a 1g dose per 100Litres
1606477669382.png

1606477701748.png

Packs plenty of 'N' little low in Mg,K,Fe and Mo compared to other high tech regimes
 

dw1305

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Hi all,
Packs plenty of 'N' little low in Mg,K,Fe and Mo compared to other high tech regimes
I assume it was <"developed for the USA">. If I wanted to create a fertiliser that produced a pretty instant greening response, it would be something with a lot of nitrogen, and probably in the form of urea, to reduce the risk of <"fertiliser burn"> in terrestrial plants.

My guess is that is why <"Tropica, ADA etc"> use urea as their nitrogen (N) source, <"it only adds N">, it is cheap to buy, non-toxic at low doses, doesn't burn and gives you a quick greening response.

From my point of view its main benefit would be the colour, <"quick response"> and <"cheapness">.
I've been mixing enough into a two litre milk carton to give me a light sky blue tint and watering the house plants with it. I've also sloshed a little bit into the tanks. I'm not recommending this, and it isn't very scientific, but so far so good.
My plants are <"~always nitrogen deficient"> so if I don't get a pretty instant greening I know that another element (<"most likely magnesium (Mg)"> or iron (Fe) is <"Liebig's limiting nutrient">.

cheers Darrel
 
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