Hi Trishfish,
So far as I can tell, it is a test for ammonia that utilizes a substance called Nessler's Solution (or Reagent).
Here is what I found about it on Wikipedia:
http://en.wikipedia.org/wiki/Nessler's_solution
I'm not sure how it differs from other ammonia tests. Perhaps somebody else can shed some light on the subject?
Thanks,
Mike
