Total Nitrates

[Damsel13]

I was reading about bactieral infections and came across something confusing... a web publication by Albert J. Thiel, copy 1997 said that if your N-N03 is 60-80 ppm the "real" nitrate level (total nitrate) is between 260-350 ppm?

Can you help me understand please?
Thank you in advance.

 

[joker577]

I know I'm wrong so i'll let the professionals handle the question, but my guess would have to be that perhaps since you're only testing 10 ml of water the actual nitrates for the entire tank is much more than in the testing water

 

[tatuvaaj]

Damsel13,

Nitrate concentration can be given in two ways: either as NO3-N or NO3. The first one refers only to nitrogen in nitrate while the latter reports nitrate as a ion including the three oxygen atoms. Because NO3 is heavier than N, results reported as NO3 are larger when the concentration is given as weight like mg/l or ppm.

NO3 is about 4.4 times as heavy as the nitrogen alone and that's why 60 ppm NO3-N is equal to ~260 ppm NO3.

A. Thiel's use of words are very confusing as this has nothing to do with either "real" or "total"

 

[Damsel13]

Hummmmm... will have to mull this around for quite some time.
Thank you both for answering.

 

[Boomer]

Hi tatu

Good post buddy

Damsel

Let me expand on tatu's post. Chemists often do not care about things like O but only things like N or P. Thus, they give P or N ppm values. It goes like this.

Nitrogen, oxygen and all elements have what we call molecular weight. The MW is the weight in grams of an element that equals a scientists dozen, which we call a mole. 1 mole of anything always has the same number of things, be it atoms, ions, molecules or even sand grains if you want. That number is 6.02 x 10^23 "things"

1 mole of N = 14 grams ( we round off these numbers to make it easier often)
1 mole of O = 16 grams

Nitrate = NO3, so 14 + 16 + 16 +16 = 62 grams for 1 mole of Nitrate

N-NO3, means we are measuring nitrate but are expressing it with only the weigh of N and leaving out the O has tatu has stated. So........

N = 14 grams for 1 mole

62 / 14 = 4.4 conversions

SO, 1 ppm NO3-N = 4.4 ppm NO3

This is why at time I ask if your kit is measuring Nitrate as Nitrate ion, NO3 or Nitrate -Nitrogen NO3-N.


The chem std is as Nitrate-Nitrogen but this hobby uses the Nitrate ion reading/expression mostly in kits.

If Bob says his nitrate is 0.2 ppm and Jim says his is 0.2 ppm also, they may not be the same. Jim's may really be .88 ppm ( 4.4 x 0.2). Jim has high nitrate for a reef tank whereas Bob's does not. We want to all be on the same page.

 

[Damsel13]

I actually understood that. Amazing!
I will just have to read both answers a few more hundred times so it will stick.

Thank you

 

[joker577]

Boy was I off

 

[Damsel13]

I still am way confused BUT I did notice that in the article by Thiel he said N-N03 and both you Boomer and tatuvaaj have said N03-N that would be correct? Just a small point in a long learning process. But I can't think of anything more fun than to learn!

 

[Boomer]

The CORRECT way to write it is NO3-N. Some just incorreclty write it backwards, i.e., N-NO3 but it is the same thing.

 

[Frankie]

Thanks for explaining this Boomer. I am still struggling a bit with it but getting a better understanding the more i read it. (three days so far)

 

[Skeptic9962]

ive been wondering about this too found out i am using a test kit that uses nitrate-nitrogen (NO-2-N) this means that its whatever ppm i get from the kit times 4.4 am i corect?

if so then is the Elos line for nitrate the same way? cause im almost out of this ocean master test kit packets for it and ill just go buy something alot more acurate and that actually tells me the real numbers that i have....

 

[Boomer]

Skeptic


nitrate-nitrogen (NO-2-N)

You mean nitrite-nitrogen (NO-2-N) or nitrate-nitrogen (NO-3-N)
It would be the same as N-NO3 and if is was N-NO-2 then, the same as N-NO2;


For N-NO2 or N-NO-2
1 mole of N = 14 grams ( we round off these numbers to make it easier often)

1 mole of O = 16 grams

Nitrite = NO2, so 14 ( 1N) and (2 O2) 16 + 16 = 46 grams for 1 mole of Nitrite


46/ 14 = 3.3 conversions

SO, 1 ppm NO2-N = 3.3 ppm NO2

 

[Skeptic9962]

ah ok yeah i was reading the wrong part of the test kit it was NO3 do you happen to know if the elos or salifert test kits are just done in NO3? or are they the same as mine? in NO3-N

 

[Boomer]

Almost all in this hobby are as NO3. Only "real" kits are in N-NO3, i.e., LaMotte, HACH, etc. Reason it is a international water testing std, not that it is more right. Salifert is NO3 as is Elos The only N-NO3 is this hobby, IIRC should be Kordon and AS/IO ( Instant Oceans). So what one do you have, are you afraid to say

 

[packer]

So if you use Salifert do you need to multiply it by something to get a true nitrate reading?? If the color reads 2ppm on salifert what is the nitrate in the tank??

 

[Boomer]

Salifert is as NO3, not N-NO3. So, 2 ppm Salifert is 2 ppm Nitrate in the tank. No conversion needed.

 

[packer]

Whew! Got nervous for a minute thinking I had to up what the test was reading to a yucky nitrate level. Thanks for the info.

 

[Skeptic9962]

yeah the test kit ive been using and curently switching to elos but for nitrate, nitrite, amonia, and PH i use Instant ocean (ocean master test kits) so best bet would be buying all new sets of elos asap?