Calling Any Chemists- How Do Ammonia Deoxifiers Work?

[TwoTankAmin]

hobby- a small favor if you would be so kind. I have paper which investigates low levels of total ammonia. They are expressing the levels in a scale with which I am not familiar. Here is an example:
 
([TAmm])=0, 70 and 225 μmol l–1
 
Can you give me an idea of what these levels would be in mg/L (aka ppm in water). I know they should be pretty low levels, but I am interested because they tested these level as a growth stimulant in farm raised salmonids (some of the most ammonia sensitive fw fish). They ran the larger scale test over 71 days. If you are curious, the full study is here:
http/jeb.biologists.org/content/207/12/2043.long
 
Thanks

 

[hobby5]

There is something called molecular mass of a certain substance. For ammonia (NH3) this is 17.0 g/mol. Using this your values should correlate to 1.2 and 3.8 ppm, respectively.

 

[TwoTankAmin]

Thanks hobby. NH3 is actually 17.03 (I see) but NH4 is 18.03. Since the Total Ammonia in the study were extremely low levels of NH3, I think the molar mas used would be much closer to 18 that 17, how does that change the number you supplied, do they go up or down?
 
Incidentally, I have been using molar mass for calculating how much NO2 and yjrm NO3 1 ppm of total ammonia could create. I never realized this was the key to the conversion you supplied. I come up with:
 
1 ppm of mostly NH4 --> 2.55 ppm Nitrite --> 3.44 ppm Nitrate (or pretty close to those numbers) The fun part is how using the nitrogen scale, instead of the total ion scale, they are all basically 1.0.
NH3 = NH3-N * 1.21589
NH4 = NH4-N * 1.28786
NO2 = NO2-N * 3.28443
NO3 = NO3-N * 4.42664

 

[hobby5]

Its a simple multiplication, therefore the values for using molecular mass of NH4+ would be about 5% higher (nothing important).

 

[TwoTankAmin]

Thanks again. What is amazing is this research basically put some of the most ammonia sensitive species of fw fish into 1.25 and almost 4 ppm of total ammonia for 70+ days and they didn't die. While during the first 60% of the time it tended to slow or barely effect growth and then that changed and it boosted it. The key to the whole thing not trashing or killing the fish was the low pH and very cool temp of the water.
 
The universe has a funny a way of working things out, The point of this thread was to find another way to show that TA readings during cycling with fish are not the numbers to which one should react, rather is is the NH3 component that is. That failed and instead it ends with another interesting research study which indicates exactly what the thread was trying to show.

 

[hobby5]

Thanks again. What is amazing is this research basically put some of the most ammonia sensitive species of fw fish into 1.25 and almost 4 ppm of total ammonia for 70+ days and they didn't die. While during the first 60% of the time it tended to slow or barely effect growth and then that changed and it boosted it. The key to the whole thing not trashing or killing the fish was the low pH and very cool temp of the water.

I was wondering the same thing. But do you call 7.6 low pH? Did other studies use higher temperatures?

 

[TwoTankAmin]

The work was done in two parts.The first was a smaller sample using 200 fish. The pH and temps were higher in this phase than in the second part where they looked at 1400 fish at a much lower pH and temp. the first study was at about 7.6 pH and 15 C while the second at 6.3 pH and 6.5 C. The combination of th lower pH and temp. in phase two make a huge difference in the NH3 content.
 
I have looked at a number of similar type studies in terms of the ammonia but not in terms of the fish used etc. A great deal of the research tends to center around farmed and most often, food fish. Much of the time the studies focus on LC50 numbers for 24 - 96 hour periods as opposed to less serious problems. There are studies out there for chronic effects such as the one here. Some even look at lower concentrations. One of the more studied fish that are common to aquaria are zebra danios.
 
What I have seen are that all of them use NH3 as the critical variable. They all reference total ammonia and most give the data for this as well. Most of them will also measure using the nitrogen scale.
 
But here is something for folks to consider. When it comes to dealing with ammonia in aquaculture, it is usually a whole different ballgame than what most of us experience with tanks. Aquaculture shares a key feature with large public aquariums. Water changes are very rarely an option for solving problems relating to nitrification. When millions of gallons are involved, there are no 50% water changes. Here is a link to a 2004 article on this very topic- ammonia in huge ponds. The one part of it I do not agree with is the section on adding bacteria. I think today there are bacterial amendments that will work and which do not contain the bacteria which break dowm organics and make ammonia. Adding Dr tim's product which contains only live nitrifying bacteria would yield a much different result than trying to add Stability which contains the sort of bacteria that would likely exacerbate rather than mitigate an ammonia spike in a large outdoor aquatic system.
 
If you are curious about how fish farms look at dealing with "cycling" related problems, have a read here. It is good plain English and easy to understand.
http/www.ca.uky.edu/wkrec/ManagingAmmonia.pdf

 

[TwoTankAmin]

hobby- I was looking for something else and came across this abstract (perhaps you have access to the full study). It seems to support my assertion that AOB can increase their oxidizing capacity, but I am not sure from just the abstract. Ny feeling is even if nitrification is an ongoing process at the cellular level. It appears that there is some degreeoff variability as to a cell being able to increase processing capacity in the presence of increased ammonia.
 

 
No clear correlations were observed between the cell numbers of AOBs or Nitrospira and their maximum rates, because the maximum cell-specific ammonia- and nitrite-oxidation rates varied remarkably over the ranges of 1.1-11.9 and 2.4-21.6 fmol-N/cell h, respectively. To explore the factors controlling maximum cell-specific nitrification rates, the relationship to influent nitrogen loads per AOB or Nitrospira cell numbers was investigated. Fairly good correlations were obtained. Considering the effluent ammonia and nitrite concentrations were zero and only Nitrosomonas halophila had a role in ammonia oxidation over the period, we conclude that the amount of nitrogen oxidised per AOB or Nitrospira cell numbers likely controls maximum cell-specific ammonia- or nitrite-oxidation rates, respectively.

from http/www.ncbi.nlm.nih.gov/pubmed/20389005

 

[hobby5]

Sry I got no access either. I would say most metabolic pathways have some variablility and can, depending on demand/substrate availability, be used at different rates. Furthermore the capacity of many pathways can be up- or downregulated by the cell. But atm I see not where that becomes relevant for our hobby. When you start a new tank there are no bacteria, hence one needs to grow "capacity" first. Is it important if we get more capacity by upregulation or be growing cell numbers?

 

[TwoTankAmin]

My observation has to do with nitrification rates. you noted that the bacteria are constantly uptaking ammonia. I thought you implied this was at a steady rate. My point is the bacteria can vary their ability to process ammonia. This relates to knowing what is going on relative to AOA. There is a lot of research being done now on the AOA vs the AOB. Much of it relies on bacterial counts or counts of genetic markers for amo. Apparently this is not such a reliable indicator. The AOA reproduce to increase the ammonia oxidizing capacity of the colony. The AOB do not need to reproduce to do this, up to a point. They are able to simply process more ammonia.
 
Basically, this is indicating is that to double the amount of ammonia being processed does not necessarily require twice the amount of bacteria. And this impacts what organisms might be handling what in systems with mixed bacterial and archaeal members.
 
But I am amused here. I made the point that to the hobbyists ammonia is not constantly be converted that we see it in stages and you looked at this from the other side- as a microbiologist. Now I am looking at the microbiology and you are looking at it from the side of the hobbyist. But where I see this as being relative to the hobby is not so much in the initial cycling, but in the production of additional ammonia after it has been established, Say by removing some media to see another tank or by increasing the bio-load in a tank through the addition of new fish. It would appear that that bacteria can respond to this, to a point, without having to go through the process of reproducing which would take more time.
 
But I have another question foryou which I hope you can answer relative the the idea that HN3-NH4 balances are instant and somewhat uniform in a tank. I have a 55 gal. tank which I target for a pH of 6.0. I do weekly water changes on the tank and have to take steps to lower the pH. I run a digital monitor on this tank which gives continuous reading for TDS, Temp and pH. Sometimes mid week or during the water change process the tank fails to be at the desired level. To correct this I dose muriatic directly into the water. I first shoo the fish to the opposite end of the tank and then add the acid. I do this et the end of the tank where the probes are located. Here is what happens.
 
The acid goes in and it takes about 30-60 seconds for the Ph reading to begin dropping. It usually drops by a full point or two. After a bit of time the pH reading start to rise as the acid gets circulated through the tank. Eventually, I check the readings and they show a net change of 0.2 or 0.3 in pH. What has happened is initially the pH is 4.8 at one end and 6.3 at the other and over the next 10 to 15 minutes it all balances out. Basically the pH effects are spreading from one end to the other until it is a uniform level. My question is what is happening to the NH3 and NH4 balances in different parts of the tank.? It seems to me you must have different ammonia balances in different parts of the tank which then change back and forth many times as the pH becomes uniform? I am really curious about how this is working.

 

[hobby5]

Sry I don't got time to dig too deep into this subject atm. But what I got from the papers you pointed me too is that AOB seem to be the main species to utilise ammonia. Remember the AOB are chemolithotrophs, which means the oxodation of ammonia is there main (single?) source of energy for growth. So it makes sense for them to have additional capacity ready in case ammonia concentrations surge so they can fill their energy stores quickly or even grow. This even more makes sense if you see that ammonia levels in nature are not constant but vary with time of the day/year. I don't know about AOA, are they dependend on ammonia oxidation too or is it only an extra energy source for them? If the AOA were the single species present, maybe they could regulate their capacity too, but this has so far not be seen as the AOB are dominant.

The pH adjustment you do in your tank sound very risky to me. Those huge and quick changes in pH will stress your fish very much. Concerning the ammonia distribution, yes you will have different ratios of NH3/NH4+ in different parts of your tank as the ratio is tightly coupled to pH.

 

[TwoTankAmin]

Trust me on those pH changes, for these fish its OK. Bear in mind in nature they can be found at some times of the year in water as low as a hair under 4.0. The key is to keep the TDS down as well. Since adding acid increases the TDS, mixing in RO water helps. It does more than drop the TDS so the acid addition doesn't pushthem up, it also mitigates the KH which in turn makes changing the pH easier to manage. I also use a combination of alder cones, catappa leaves and occasionally some peat as well as driftwood to help keep the tank more stable. I also run a three way digital monitor on the main tank.
 
The first time I watched this acid addition done was when I picked up wild angels from the importer. He worked another job as well and he worked things out so his wife could do the water changes on the tanks but did not dose the acid. He would do so when he came home from work. The day I picked up my fish he had worked 1/2 a day and he was doing acid additions when I was there. I could not believe my eyes and discussed it with him. He had done this for a couple of years by then. He explained that buffers did not work well and the acid does. bear in mind his tanks were under 5.0 and on down to almost 4.0 So what I watched was him taking a tank with about 30 or 40 wild angels in it go from about 5.5 down to 4.4 in a couple of minutes. The fish did not seem to notice. He did this in several tanks. Unlike him I do shoo my fish to the opposite end of the tank if I need to add some acid mid-week between water changes.
 
While the conventional wisdom argues against doing this, there are always exceptions to the conventional wisdom. I have some plecos that spawn. They are triggered by the changeover from dry to rainy season. It is typical when breeding such fish to do a raid drop in both TDS and Temperatures a trigger. I am talking about dropping TDS from 160 ppm to under 70 and lower while dropping the temperature by 10F or a bit more in a matter of minutes as well. Most folks would also tell us not to do that either.
 
Its like the convention wisdom about ammonia (to circle things back close to the original thread topic). Everyone knows ammonia is bad for fish, right? Yet that study with umols I asked you about showed those levels of ammonia initially inhibited growth but then this reversed after about 40 days and for the next 30 or so it actually acted as a growth accelerator and in the end the ammonia exposed fish grew more. There is another study with similar surprising results regarding low levels of chloramine: "Toxicity and therapeutic effects of chloramine-T for treating Flavobacterium columnare infection of goldfish."
 
It just goes to show us how variable and really interesting/surprising this hobby can be.