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i am trying to study ammonia nitrite and nitrate a bit more and
i was wondering if there is some where on here or if some one can
suggest a site where i can do a bit more studying on ammonia nitrite and nitrate
any help would be great i have been keeping fish for a long time so thought
it was about time i took a refresher coarse so i am starting at the beginning

Here is a Google search for Aquarium nitrogen cycle.

http://www.americanaquariumproducts.com ... Cycle.html
I like this site - gives a lot of detail.

Hi all,
The linked article is OK, even though he ignores the main source of NH3, which is diffusion from the gills of the fish.

Personally I'd recommend the "Skeptical Aquarist" for all this sort of information <http://www.skepticalaquarist.com/nitrogen-cycle>, all the articles are well written and "get the job done".

If you want to buy a book I'd buy Diana Walstad's "Ecology of the Planted Aquarium", it is well worth buying and if I only had one book this would be the one.

cheers Darrel

There's an article I wrote here on PC, but it just covers the basics, really.

dw1305 wrote:Personally I'd recommend the "Skeptical Aquarist" for all this sort of information <http://www.skepticalaquarist.com/nitrogen-cycle>, all the articles are well written and "get the job done".

Thanks so much for the link, Darrel!

[1] In the subsection "Ammonia's less toxic form, ammonium (NH4)", it says: "In acidic water, that is with pH levels below pH7.0, ammonia tends to collect an extra hydrogen ion. The positively-charged, or ionized, form of ammonia is NH4+, called ammonium. In this ionized form it is much less toxic to fish."

And then below it says: "At pH 7.0 ammonia is about 0.33% of Total Ammonia Nitrogen (TAN)...".

I understand the numbers, which state 99.67% of NH3 exists as NH4+ at pH 7 and room temp. While technically correct, it is the "tends to collect" words that can throw one off because they don't convey such a predominant equilibrium shift towards NH4+.

[2] Same section: "It might be good to recall that toxic NH3 incurs chronic gill damage at levels as low as 0.05 mg/l. With time, gill damage becomes irreversible."

Very good to know. 0.05 mg/l = 0.05 ppm. So if one measures 0.25 ppm TAN, this means that 0.25 ppm x 0.33% = 0.00083 ppm = 0.83 ppb of NH3 in the tank water (the remaining 0.249 ppm is NH4+). NH3 + NH4+ = TAN.

So at 0.25 ppm TAN, there is only 0.00083 ppm NH3 in the water, which is 60 times below the chronic-damage-causing 0.05 ppm NH3.

Are these consideratons correct? Given that we strive for the TAN reading of 0-0.25 ppm, I understand we strive for a very large margin of safety, right?

Now, the caveat is that a standard liquid ammonia test (mine has always been API) actually tests for the TAN not for NH3 alone - is that something you'd agree? The article says there are two kinds of tests - for NH3 and for TAN. IDK, I never seen such two different tests; all I saw says "ammonia" and that's it. What I know is that the instructions on (and my experience with) the "Ammo-Lock" (API) say that the water still tests positive for ammonia but it is converted into a "non-toxic form". There were emergency times/transport times when my API test would read 6-8 ppm ammonia (with the right dosage of Ammo-Lock present) and my fish would behave fine.

Will continue reading, so more may be later. Thanks so much again!

does ph have any effect on nitrite whether its less
toxic at a lower ph or a higher ph i have been reading
that nitrite is actually more toxic to fish than ammonia
is but i dont know if it is or not i have study the nitrogen cycle over and
over i did my first nitrogen cycle diagram at eight years old
i have learned a lot more of them article's they are well worth a
read as a refresher i matured to external filters in about 8 days
using only pure ammonia i found it a lot easier than doing it the other
way i normally do it with mature media or using a off the shelf cycle starter

Hi all,

So at 0.25 ppm TAN, there is only 0.00083 ppm NH3 in the water, which is 60 times below the chronic-damage-causing 0.05 ppm NH3. Are these consideratons correct? Given that we strive for the TAN reading of 0-0.25 ppm, I understand we strive for a very large margin of safety, right?

Yes, it is all a bit confusing, you also really have to take temperature and concentration into account as well, and the relationship is only linear over a small range of pH values. You should be able to work out the values from this curve, but with the caveat that you really need an ion selective electrode for measurement and other cations (like Na+, Ca++) can interfere with the reading whatever method we use.


Free ammonia = NH3.

This image came from <http://www.nico2000.net/analytical/ammonium/NH4lib.html> where there are tabulated and graphical values and a description of the workings of the ion selective electrode. There is also really comprehensive summary of the "Acid-base Chemistry of Aquatic Systems" at: <http://neon.otago.ac.nz/media/content/d ... sebook.pdf>.

Nessler type test kits test for TAN, because they make use of the pH NH3/NH4+ relationship. If we raise the pH of the solution high enough we know all ammonia/ammonium will be as NH3, and this then reacts to form a yellow compound. Equation below (alkalinity comes from the 4OH-)
NH4+ + 2[HgI4]2− + 4OH− → HgO·Hg(NH2)I + 7I− + 3H2O

Winkler (salicylate) tests test for NH3 (again by raising pH) and are probably more useful, but you can't really rely on either type. Details for Winkler test here: <http://www.hach.com/epa>.

Now, the caveat is that a standard liquid ammonia test (mine has always been API) actually tests for the TAN not for NH3 alone - is that something you'd agree? The article says there are two kinds of tests - for NH3 and for TAN. IDK, I never seen such two different tests; all I saw says "ammonia" and that's it. What I know is that the instructions on (and my experience with) the "Ammo-Lock" (API) say that the water still tests positive for ammonia but it is converted into a "non-toxic form". There were emergency times/transport times when my API test would read 6-8 ppm ammonia (with the right dosage of Ammo-Lock present) and my fish would behave fine.

We know how AMQUEL works, because it has a patent, and I would be pretty sure that "Ammo-lock", "Prime" etc. use a similar method, although the companies won't tell you. Searching through the posts I found that both Viktor and I posted on a thread covering this on PC in 2011 <http://www.planetcatfish.com/forum/view ... l&start=40>.
The relevant bit is:

Yes, this is to neutralise the chlorine, the newer, "better" conditioners use EDTA and sodium hydroxymethanesulfonate (or similar). The EDTA chelates any heavy metals (as long as Fe ions aren't present in large amounts) and the hydroxymethane - end of the molecule reacts with ammonia to form a non-toxic, stable water-soluble compound "aminomethanesulfonate". The sulfonate end of the molecule reacts with both free-available chlorine, and combined-available chlorine in chloramines. Any ammonia (from the break down of the chloramine) is then mopped up by the sodium hydroxymethanesulfonate.......

This process can then potentially continue infinitely, although if you didn't do any water changes you could end up in a situation where you had a huge reserve of bound NH3, which would be released if you ever stopped adding more sodium hydroxymethanesulfonate.

does ph have any effect on nitrite whether its less toxic at a lower ph or a higher ph i have been reading that nitrite is actually more toxic to fish than ammonia

Nitrite NO2 is toxic, but again it isn't a simple process. In this case pH isn't particularly relevant, but temperature and the presence of other anions (Cl- etc) are. There is a really good review paper "Nitrite influence on fish: a review" at:<http://vri.cz/docs/vetmed/50-11-461.pdf>, I'm not sure how easy that is to access (I can but I'm at work), but if you can't get it there is a less in depth, but still good review here <http://www.merckvetmanual.com/mvm/index ... 170406.htm>.

cheers Darrel

This is a pet topic of mine and I have been researching it heavily for the past couple of years. While a lot of the links offered above are interesting (and I have read most of them), you will find much better information via Google Scholar. http://www.google.com/schhp?hl=enTry using the following search terms to use: "Nitrite toxicity and tropical fish", "Ammonia toxicity and tropical fish", "Nitrite toxicity and tropical fish"

The research into this subject is excellent and most informative. I can offer few of my bookmarked links. Unfortunately, much of the full texts for things are only available via subscription or for pay. Some are free. But if you read enough abstracts you can learn a lot.

NH3 levels are mostly impacted by pH levels with temperature levels being a secondary consideration. While NH4+ is way less toxic, prolonged exposure will negatively impact fish.

Understanding ammonia, nitrite and nitrate is a dual edged sword. Their effects on cycling issues and bacteria is not the same as the effects on aquatic life forms (fish and inverts etc.)

Here are a few interesting reads:
Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish http://www.scielo.br/pdf/aa/v38n4/v38n4a23.pdf

Acute and chronic toxicity of ammonia, nitrite, and nitrate to the endangered topeka shiner (Notropis topeka) and fathead minnows (Pimephales promelas) http://onlinelibrary.wiley.com/doi/10.1 ... edMessage=

Ammonia Toxicity http://onlinelibrary.wiley.com/doi/10.1 ... edMessage=

From the Merck Veterinary Manual- Nitrogenous Compounds: http://www.merckvetmanual.com/mvm/index ... 170406.htm
Free ammonia and free nitrous acid inhibition on the anabolic and catabolic processes of Nitrosomonas and Nitrobacter http://www.emeraldinsight.com/journals. ... id=1042228

Nitrate Toxicity: A Potential Problem of Recirculating Systems http://www.atlantech.ca/public/articles ... uality.PDF

Nitrite in Fish Ponds https://srac.tamu.edu/index.cfm/event/g ... sheet/110/

Pond pH and Ammonia Toxicity Published as, Daily pH Cycle and Ammonia Toxicity, World Aquaculture, 34(2): 20-21 https://srac.tamu.edu/index.cfm/event/g ... sheet/110/

Here are some suggested search terms to use to search Coogle Scholar: "Nitrite toxicity and tropical fish", "Ammonia toxicity and tropical fish", "Nitrite toxicity and tropical fish"

i said i was wanting to do a refresher course
well that is going t to keep me busy reading when i cant sleep
at night

Hi all,

This is a pet topic of mine and I have been researching it heavily for the past couple of years. While a lot of the links offered above are interesting (and I have read most of them), you will find much better information via Google Scholar.

I couldn't agree more, that is the great thing about science, the more you know the more you find out there is to know.

I think one of the main problems with the science side of our hobby is that you are dealing with "Aquarium product" companies who are often less than transparent about what their products contain and how they work. Often I think that rather than using science to enlighten they are using it to confuse their customers.

Any-one who is serious about a subject like this has access (via Google Scholar) and to a wealth of information that wasn't even available to University researchers 15 years ago.

You might like to have a look at links for "BOD & aquaculture": <http://scholar.google.co.uk/scholar?hl= ... _sdt=1%2C5> as well.

I think there should be open access to Crab, R. et al. (2007) "Nitrogen removal techniques in aquaculture for a sustainable production" Aquaculture 270:1–4, pp 1–14.
Both the article, and the 121 papers that cite it, are well worth a read:
Abs.

As the aquaculture industry intensively develops, its environmental impact increases. Discharges from aquaculture deteriorate the receiving environment and the need for fishmeal and fish oil for fish feed production increases. Rotating biological contactors, trickling filters, bead filters and fluidized sand biofilters are conventionally used in intensive aquaculture systems to remove nitrogen from culture water. Besides these conventional water treatment systems, there are other possible modi operandi to recycle aquaculture water and simultaneously produce fish feed. These double-purpose techniques are the periphyton treatment technique, which is applicable to extensive systems, and the proteinaceous bio-flocs technology, which can be used in extensive as well as in intensive systems. In addition to maintenance of good water quality, both techniques provide an inexpensive feed source and a higher efficiency of nutrient conversion of feed. The bio-flocs technology has the advantage over the other techniques that it is relatively inexpensive; this makes it an economically viable approach for sustainable aquaculture.

cheers Darrel