Ammonia/Nitrite/Nitrate ratios?

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pseudorand

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I think I've dealt with an ammonia problem, but nitrates have remained steady at 5ppm even though ammonia now reads 0, down from 0.25. (Nitrites also read 0). This is expected, because:

2xNH3 + 2x02 => 2xNO2 + 3xH2
2xNO2 + O2 => 2xNO3

I realize that's horribly oversimplified, but the point is that we have the same number of nitrogens throughout the process, meaning 1ppm NH3 is converted into 1ppm NO3, correct? I shouldn't expect to see a spike in nitrates by reducing ammonia by 0.25ppm because my test kit isn't accurate enough to distinguish between 5ppm and 5.25ppm nitrates, right?

I actually dealt with the ammonia via a ~50% water change, but that should have only pulled it from 0.25 to 0.125. I also added bacteria starter, and I'm trying to figure out if/when it will happen again. Did the bacteria start (+ existing bacteria) eliminate the other 0.125ppm? I'd need a very sensitive nitrate test kit to confirm that, correct?
 
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Krixic

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Glad to see I did not completely throw out my chem knowledge as I was somehow able to follow along with that first bit lol. Yes, I believe that it is unlikely to expect any sudden increase in nitrates from your reader as ATI especially is not exactly know for its dead eye accuracy. To determine whether that last bit of Ammonia is truely gone, you could get Hanna's new LR Nitrate reader. While yes it is designed to read samples between 0-5ppm, there is a dilution procedure provided by hanna that can allow you to read between 0-50 (not sure how this would affect accuracy. Frankly, I think that its likely that your ammonia levels are at or close to 0 especially if you added live bacteria starter. Your ATI just is not picking up the 0.25 increase in Nitrates.
Hopefully this helped! Not sure if I answered your question or not...
 

Randy Holmes-Farley

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but the point is that we have the same number of nitrogens throughout the process, meaning 1ppm NH3 is converted into 1ppm NO3, correct? I shouldn't expect to see a spike in nitrates by reducing ammonia by 0.25ppm because my test kit isn't accurate enough to distinguish between 5ppm and 5.25ppm nitrates, right?

That is incorrect because one ammonia weighs far less than 1 nitrate.

So 1.0 ppm ammonia becomes 3.6 ppm nitrate.

The other complication is the with many kits, 1 ppm nitrite can read falsely as 100 ppm nitrate. So if any nitrite is present, nitrate testing can be inaccurate.
 
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pseudorand

pseudorand

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That is incorrect because one ammonia weighs far less than 1 nitrate.

So 1.0 ppm ammonia becomes 3.6 ppm nitrate.

The other complication is the with many kits, 1 ppm nitrite can read falsely as 100 ppm nitrate. So if any nitrite is present, nitrate testing can be inaccurate.
PPM is by mass then, got it. My .125ppm ammonia would have become .45ppm nitrate, which is still far below the resolution of my nitrate test kit, so I shouldn't expect a nitrate spike as quickly as the ammonia spike.

What's the million in ppm, water? (i.e. 1ppm is 1 gram of no3 for each million grams of h2O rather than per count of molecules as I had assumed).
 

brandon429

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also

curious if there ever was a .25 that's a common reading for the kit, known as a common error read even if it blanks on other samples/noted trend
can you show the reef tank the water sample came from? there are certain details we need to see in common full tank shots that can tell us if you had an ammonia problem at all, from the pics not the test kit

I was most curious to see/find the clues that ever allowed an initial accurate reading of .25
 
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Randy Holmes-Farley

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PPM is by mass then, got it. My .125ppm ammonia would have become .45ppm nitrate, which is still far below the resolution of my nitrate test kit, so I shouldn't expect a nitrate spike as quickly as the ammonia spike.

What's the million in ppm, water? (i.e. 1ppm is 1 gram of no3 for each million grams of h2O rather than per count of molecules as I had assumed).

ppm can be in molecules (typical in a gas) or weight, or even volume (liquids). In reef aquarium usage, it is always mass unless talking about gases (like CO2 in air).

This has more for all sorts of units:

The Units of Measure of Reefkeeping by Randy Holmes-Farley - Reefkeeping.com

ppm is a unit of proportion equal to 10-6. It is equal to 10-3 g/kg and 1 mg/kg, and is close to 10-3 g/L or 1 mg/L (in fresh water; in seawater, it equals about 1.023 x 10-3 g/L).

It is often used to measure the concentrations of different species in reef aquaria. A calculator for various weight-related units can be found here.
 
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