Backyard Aquaponics
A place to discuss aquaponics

I think the chemical formula is

NH3 + stuff -> NO2- + stuff


I assume that the stuff doesn't include N2, i.e. no consumption or production of dissolved atmospheric nitrogen. Also assuming stuff has no nitrogen content. e.g. the same N in the NH3 becomes the N in NO2 at a 1:1 ratio.


NH3 has a molar mass of 17. NO2- has a molar mass of 46.

46/17 = 2.7

So 1 gram of NH3 converted completely produces 2.7 grams of NO2. Which means 1 ppm reduction in NH3 should equate to a 2.7 ppm increase in NO2 (assuming the NO2 isn't being itself converted, which is of course not really a valid assumption in a aquaponics garden).


Is any of that wrong?

In aquaponics you're not converting something into something else in controlled conditions, so while your calc's may be correct, it will never pan out exactly that way in your water parameter readings.

If you're wondering what level your Nitrite spike may get to during the cycling process, I have been involved in, or privy to the records from the cycling of many systems, and in the majority of cases the Nitrite spike has peaked at around 2x whatever the Ammonia level had reached... But, I've also seen everything from zero Nitrites through to 4x the level the Amm had reached.

I've missed Nitrites spikes (the 0.00ppm referred to above) because they've happened so quickly, suggesting the different types of Nitrifying bacteria pretty much developed simultaneously. I've seen many Nitrite spikes over in 2-3 days, and I've seen one that was sustained over nearly two weeks... There are no absolutes in aquaponics.

In a cycled, well established system you won't (shouldn't) see Nitrites in your tests. So all this will be irrelevant.

Thanks for the reply. I was getting a nice nitrite spike but wasn’t see NH3 budge. After running through the calcs, it seemed that NH3 moves slower than ‘trites. Also, in the NH3 range it could have moved 1-2ppm without changing color much. So those two facts made me feel things were normal, but I wanted to confirm #1 with the community.