Derek Broughton wrote:
Altum wrote:

Yes, but it's _still_ much less toxic than ammonia.
Put it in alkaline water (as in most ponds) and it promptly loses a
proton and becomes ammonia.

"most ponds"? I think you'd be hard pressed to prove it. I'm not convinced
your chemistry is right, either - mine's way in the past, but it doesn't
seem valid to me.

What part of "pKa of ammonium = 9.2" is unclear? You can verify that
number anywhere. If you have forgotten what a pKa is, you may want to
go back to a chemistry text and review the Henderson-Hasselbach
equations and buffering chemistry. Knowing about the pH-dependent
equilibrium between less NH4+ and NH3 is fairly fundamental to aquarium
and pond chemistry.

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