# LaMotte NO3 Kit



## Rob Tetrazona (Jun 21, 2005)

This question is directed towards Matt "The Leader Dude" :hail:, but anybody is welcome to chime in. Matt has probably been wondering when I was going to ask this question. The answer is when I finally got around to testing my water!

I'm new to LaMotte testing kits. I'm used to Aquarium Pharmaceuticals kits which are fine until they turn different shades of red, coupled with my color blindness, I can't tell the difference between 40ppm and 200ppm of NO3. 

I tested the water in one of my tanks last night and realized that the do-hinky that you compare your water color to after you add the reagents and wait patiently only goes up to 10ppm! Maybe I'm missing something here, like an instruction manual, but is a test kit that only tests up to 10ppm for NO3 really useful? I think 20ppm is ideal for my tanks with the 20:2 (10:1) NO3O4 ratio, but if I'm over 20ppm, I want to know and by how much. 

Somebody please clue me in on what I have missed. Do I need to order a do-hinky that measures 20ppm and greater? Does such a do-hinky exist? I'm still waiting to be impressed by the French.


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## Laith (Sep 4, 2004)

As far as I remember, the LaMotte NO3 test kit actually gives results in total Nitrogen, not NO3.

Multiply the result the kit gives you by 4.4 to get mg/l (ppm) NO3. So a LaMotte reading of 10 (total Nitrogen) is actually 44mg/l of NO3.


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## wiste (Feb 10, 2006)

a LaMotte reading of 10 (total Nitrogen) is actually 44mg/l of NO3. - assumes no nitrites.

Per the instructions:
To convert the test result to ppm Nitrate (NO3), muliply by 4.4.
Nitrite interferes at all levels. Use the following equation to compensate for nitrite interferences:
Test result (ppm) - (Nitrite-N (ppm) x 5.5) = true Nitrate-- N reading
However, nitrites are probably negligible unless the tank is cycling.


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## MatPat (Mar 22, 2004)

Rob,

Both Laith and Wiste are correct about the NO3 readings. You need to multiply your reading by 4.4 to get Nitrate. You're not the first to have this question and I should have pointed it out to you when I gave you the kit. I also believe everything Wiste stated somewhere in the instructions...I hope I gave them to you 

HOw does the LaMotte NO3 kit work since you are colorblind? Is it easier to compare the shades of "gray"


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## Rob Tetrazona (Jun 21, 2005)

Thanks for all of the instructions, everyone!

It's hard to say since my test results were off the chart! I'm going to back off on the NO3 dosing some to see if I can get out of the purple range. I'll let you know when I get there.


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## Laith (Sep 4, 2004)

While LaMotte kits are probably some of the best "affordable" test kits around, they are *not* infallible.

Even LaMotte kits need to be calibrated. I once tested the LaMotte NO3 kit against a series of known concentrations of NO3 and the LaMotte kit was giving consistently off the chart results.

If you want to test your tank water, be as sure as you can of the results: test your test kits!


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