How does ammonia change into ammonium

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AdHoc
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How does ammonia change into ammonium

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Post by AdHoc »

Can anyone tell me how ammonia changes into ammonium?

If I have ammonia in freshwater (temp = 19C, PH = 7.2) and I introduce saltwater (temp = 15C, PH = 8.2) the ammonia apparently changes to ammonium and is toxic to fish.

Can anyone explain what is going on chemically and the simplest way to prevent it from happening?

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AdHoc
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Re: How does ammonia change into ammonium

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[Replying to post 1 by AdHoc]

Turns out ammonia gas or un-ionized ammonia (NH3) in solution causes cellular death in the fishes central nervous system. Ammonium or ionized ammonia (NH4) is much less toxic. Both are at equilibrium as part of the total ammonia and nitrogen (TAN) at neutral PH. When the PH becomes more alkaline the balance shifts to more un-ionized ammonia and toxicity increases.

Temperature and salinity are factors as well but in the specific case I'm thinking of PH was the main driver.

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Re: How does ammonia change into ammonium

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Post by Excubis »

AdHoc wrote: [Replying to post 1 by AdHoc]

Turns out ammonia gas or un-ionized ammonia (NH3) in solution causes cellular death in the fishes central nervous system. Ammonium or ionized ammonia (NH4) is much less toxic. Both are at equilibrium as part of the total ammonia and nitrogen (TAN) at neutral PH. When the PH becomes more alkaline the balance shifts to more un-ionized ammonia and toxicity increases.

Temperature and salinity are factors as well but in the specific case I'm thinking of PH was the main driver.
This should not be it should produce NH4Cl unless you have free Nitrogen to bond with free hydrogen, and ph is about how many hydrogen ions are with in a liquid, ph = power of hydrogen. So if you have an excess of Nitrogen it would bond with free hydrogen to make NH3 and NH4 lastly where NH4Cl is Ammonium chloride.

NH is covalent and will take Cl on and become NH4 since outer shell of NH4 is uneven (1 free electron) and Cl needs 1 and since they are both gasses they share rather than steal or give an electron. There is much more and although not an Chemical engineer feel if a person want to understand atoms we should have an understanding of how elements bond at atomic level. Didn't see this before too band.

Needed to add PH is Power of Hydrogen and pertains to amount of hydrogen ions are apparent in a aquas(liquid).
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Re: How does ammonia change into ammonium

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Post by Excubis »

[Replying to post 3 by Excubis]

Well this has bothered me and I was wrong. Had to pull out my old note but found it, NaCl(Common salt)+H2O+NH3--------> OH+NH4+Cl+Na and ph is around 12, everything will stay separated/free in a aquas(liquid) solution. H2O NH3 ph of 7 (neutral)

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Post #5

Post by Willum »

There are probably good chemicals to do it, but if you can control the pH, you can use vinegar or muriatic acid - added very slowly! A drop at a time for muriatic and 1/4 teaspoon for vinegar.

But I would really recommend aquarium chemicals.

NH4Cl is very benign. Ammonium acetate is going to be more problematic. Eventually of course you just have too much of either.

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