I'm a chemist. I agree with most of the comments in this thread.

Nitrogen, as found in the air is Nsub2. The "sub" indicates subscript.
Nsub2 has little biological activity, but certain bacteria and other
organisms can "fix" nitrogen from the air and incorporate it into
biochemicals.

Ammonia is NHsub3. When ammonia is dissolved in water it is sometimes
called ammonium hydroxide or NHsub4OH. Ammonium hydroxide is a weak base.
It partially breaks down, or disassociates into the ammonium ion NHsub4sup+
and hydroxyl ions OHsup-. The "sup" indicates superscript. In addition to
other toxicity problems associated with ammonia, it is basic and will raise
the pH, i.e. increase the alkalinity of the water.

Nitrous acid is HNOsub2. Nitrous acid is a strong acid, in water it
completely breaks down into Hsub3Osup+ (hydronium ions) plus NOsub2sup+
(nitrite ion). The nitrite ion oxidizes quickly in well-oxygenated water
to become NOsub3sup+ (nitrate).

Unfortunately, none of this explains "what exactly is the difference
between NO3-N and just plain NO3." The terminology is simply not clear.

Richard

P.S. - I don't have a husband, but I do have an excellent wife.



Derek Broughton wrote in
:

wrote:

a chemist on this list? I done all the searches and have come up
with the standard "total nitrogen" thing, now I want it explained in
more detail and WHY they use this way of expressing it when they
werent doing that 20 years ago when I took the damn

Who's "they"? When I've seen NO3-N, I thought it was just an
indicator of the Nitrate - Nitrogen pathway, not a molecular
notation.