1 ppm ammonia = 1 ppm nitrite = 1 ppm nitrate?

I've always wondered if 1 ppm ammonia essentially converts to 1 ppm nitrate.  In practice it seems like it must be fairly close.  Anyone know?

Don't let fear and common sense stop you! =]

Molar mass of ammonia is 17.031 g/mol.  For the nitrite ion, it is 46.0055.  For nitrate, it is 62.0049. 
 
During the conversion from ammonia to nitrite to nitrate, basically the Nitrogen atom gets different other atoms associated with it.  Look at it like the Nitrogen atom is what stays around, but in a different form.
 
PPM is an expression of mg/L, so in other words, it is a relationship by weight.  1 PPM of ammonia means that each liter contains 1 mg of ammonia.  With a molar mass of 17.031 g/mol (1 mol = 6.022 * 10^23 ) that means that that mg of ammonia contains (6.022 * 10^23 / 17.031) / 1000 = 3.536 * 10^19 molecules of ammonia.  When those molecules of ammonia get the three hydrogen atoms replaced by two oxygen atoms to become a nitrite ion, all of a sudden we have 46.0055 / 17.031 = 2.7 times the original weight (1 mg) of nitrite in that liter of water, so now we have 2.7 PPM of nitrite.  Same number of molecules, but each one weighs more.  When those nitrite ions get an extra oxygen atom added to turn them into nitrate, we now have 62.0049 / 46.0055 = 1.35 times more weight yet again, for a total of 3.64 PPM of nitrate.
 
So, to answer your question, the way I understand things 1 PPM NH3 = 2.7 PPM NO2 = 3.64 PPM NO3, but I'm not a chemist.  If Gresh or someone with the resources to verify my thinking and math could fact check me, that would be great!
 
As a side note, one factor in how I allowed nitrates to get sky high in my 210 display tank long ago was that the LaMotte kit I was using says at the end of the instructions, "Record as ppm Nitrate as Nitrate Nitrogen (NO3-N).  To convert to ppm Nitrate (NO3), multiply by 4.4."  The kit measures the ppm of the Nitrogen atom portion of the Nitrate ion only.  The atomic weight of Nitrogen is 14.0067.  The 4.4 multiplier comes from the molar of mass of Nitrate divided by the atomic weight of Nitrogen:  62.0049 / 14.0067 = 4.427.  Yikes!  My 20 PPM Nitrate suddenly became 88 PPM once I understood what the kit was reading!!!!
 

Great info Jim!

-Adam

Awesome, thanks Jim!  I didn't think it was that far off though, I figured it might be 1 ppm ammonia = 2 ppm nitrate.

Don't let fear and common sense stop you! =]

Could have fooled me! Great info!