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Re: [APD] Re:Ammonia and Soil Substrates
No need to worry over the adjectives. The numbers speak
well, that's why I posted them and offered the graph. Some
folks think the ammonia/ammonium relationship is pretty
much an on/off thing, which is not the case.
I think I did say that low levels of ammonia can be toxic.
--- Steven Pituch <spituch at ev1_net> wrote:
> Scott said:
> >The diff in ammonia vs ammonium is slightly changed as
> >pH changes.
> "The percentage of ammonia in a solution with a given N
> changes dramatically with pH. Typically, there is a 10
> fold increase in
> ammonia for every 1 unit increase in pH as NH4+ converts
> to NH3 in the above
> equilibrium reaction. For example, if the pH increases
> from 7.0 to 8.0 the
> % of N that is NH3 increases from about 0.33% to 3.3%,
> while the % of N that
> is NH4+ correspondingly falls from 99.7% to 96.7%.
> Thus the higher the
> pH the greater the NH3 concentration and the toxicity of
> a given
> concentration of inorganic nitrogen." - D. Walstad, "The
> Ecology of the
> Planted Aquarium", 1st edition.
> So I agree that "slightly" would describe the change in
> ammonium, but I
> would prefer to use the word "dramatically", as Walstad
> does, to describe
> the increase in ammonia. I feel a factor of 10 increase
> in ammonia is
> significant and can mean the difference between life and
> death for a fish.
> Steve Pituch
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
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