Big nitrate testing discrepancy. Which to trust?

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I'd rather confirm the test was working correctly. It's like checking to see if a car motor is working, but not checking if the driver knows how to drive. lol

The test with the color standards in no way validate the overall method or the reagents or procedures used.
So then what is the best thing for me to do in this situation? I'm confident in the way I'm performing the test, and have other Hanna checkers that don't pose this confusion for me -- for example my Alk checker is always consistent w/my Salifert Alk test. I honestly wondered if something was wrong with the actual checker.
 

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So then what is the best thing for me to do in this situation? I'm confident in the way I'm performing the test, and have other Hanna checkers that don't pose this confusion for me -- for example my Alk checker is always consistent w/my Salifert Alk test. I honestly wondered if something was wrong with the actual checker.
There should be a calibration fluid with a known standard you can check it to. If the hannah checker doesn't give you the correct value within acceptable deviations, then you will know that its gone bad.
 
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There should be a calibration fluid with a known standard you can check it to. If the hannah checker doesn't give you the correct value within acceptable deviations, then you will know that its gone bad.
That's exactly what I just did, but Randy seems to think it's not worth much and/or there's something about the way I've been performing the test that may be incorrect rather than the checker itself. I was more or less asking where to go from here then if I'm confident in the way I've been performing it, and the checker passed the calibration test.

I do it like this: water to the same level each test, empty packets same way each time and get all reagent out, wipe cuvettes w/microfiber cloth, shake proper amount of time, make sure no micro bubbles, place into checker the same way it was facing when zero out... I've tested with slightly more or less water, some very small bit of reagent powder left in packet, etc, and the results are so minimally different it really doesn't matter. I suppose if the cuvettes were wildly dirty then it might, but that is not the case.
 

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That's exactly what I just did, but Randy seems to think it's not worth much and/or there's something about the way I've been performing the test that may be incorrect rather than the checker itself. I was more or less asking where to go from here then if I'm confident in the way I've been performing it, and the checker passed the calibration test.

So let's back up. Maybe I am misunderstanding what you tested as a standard.

Do you have a link to the standard?

Was it a sealed colored liquid vial that you just dropped into the machine to get a reading, or was it a clear solution that you mixed reagents into and did the whole test procedure and got a certain reading?

I assumed it was the former. If not, what I said was incorrect.
 
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So let's back up. Maybe I am misunderstanding what you tested as a standard.

Do you have a link to the standard?

Was it a sealed colored liquid vial that you just dropped into the machine to get a reading, or was it a clear solution that you mixed reagents into and did the whole test procedure and got a certain reading?

I assumed it was the former. If not, what I said was incorrect.
No, it is that, you're right -- I believe the phosphate one is the latter and in reviews folks seem annoyed w/that b/c you can only use it once.

I just wanted a way to test the machine itself, b/c I can't figure out why the readings I get with it are so different from other tests, and I don't believe there's anything glaringly wrong w/the way I'm performing the test. I figured if I could determine whether or not the machine is wonky that might point me in a better direction.
 

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No, it is that, you're right -- I believe the phosphate one is the latter and in reviews folks seem annoyed w/that b/c you can only use it once.

I just wanted a way to test the machine itself, b/c I can't figure out why the readings I get with it are so different from other tests, and I don't believe there's anything glaringly wrong w/the way I'm performing the test. I figured if I could determine whether or not the machine is wonky that might point me in a better direction.

It certainly doesn't hurt to check what you checked.

IMO, if a hobbyist can know the nitrate level to within a factor of 2, that's good enough.

With Salifert saying 20-30 ppm and Hanna sating 10-20 ppm, I'd settle on it being about 10-30 ppm, and that's good enough, IMO. (assuming no nitrite; if nitrite is present, nitrate kits will not agree since the interference can vary)
 
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It certainly doesn't hurt to check what you checked.

IMO, if a hobbyist can know the nitrate level to within a factor of 2, that's good enough.

With Salifert saying 20-30 ppm and Hanna sating 10-20 ppm, I'd settle on it being about 10-30 ppm, and that's good enough, IMO. (assuming no nitrite; if nitrite is present, nitrate kits will not agree since the interference can vary)
Okay, thanks. I'll check nitrite just to try to rule that out, esp since the last time I tested for that was when I was cycling the tank!
 

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I believe fauna marine makes a standard you can run like a regular test. In another words it's a known solution. Test against that, and if the hanna isn't within specs, you know it's reading wrong.

The "kit" hanna sells, only checks to see if the electronics work correctly(pre made solution).

 

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I believe fauna marine makes a standard you can run like a regular test. In another words it's a known solution. Test against that, and if the hanna isn't within specs, you know it's reading wrong.

The "kit" hanna sells, only checks to see if the electronics work correctly(pre made solution).


Seems like that could be very useful and be able to validate several tests thanks for sharing
 
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Um. New Hanna reagents, just did the test for the first time since last week's 12 ppm reading and got 75 ppm. That's higher than I've ever gotten on any test kit, ever outside of cycling the tank, so IDK but I'm 100% still hesitant to trust the Hanna.

Edit: The only other thing I can think is last time I took a reading I had a green cyano bloom on the sand that has since completely gone away. Could it be possible that in the absence of the cyano, this is truly where my nitrates are today? I have a light dusting of turf algae on the sand now, and some GHA starting to grow on one of my trochus snail's shell, but other than that no scary algae problems.

I'm going to test w/Salifert rn to compare...
 
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I have a little 3D printed drying rack for the vials, then I wipe them out w/a paper towel and rinse w/tank water before taking the sample. And I’m super meticulous w/Hanna — wiping the cuvette w/a microfiber cloth and making sure no bubbles before taking the reading. Test water collected w/a clean pipette. Stopwatch on my phone for all.

The weird thing is they are all individually consistent — API always high, Hanna on the lower end, and Salifert typically somewhere in between.

a few ppl have recommended Nyos so I might try that until Hanna has HR nitrate reagents available again.
There’s a difference between an accurate test and precise test. They are not the same.
 

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I'm sorry I don't understand what you are trying to say with that. Do you have some help to offer?
Precision is how close you are to the actually number and accuracy is how close your test results are to each other. Therefore you should be looking for a test that is more precise. Just trying to explain why your test result are the way they are.
 

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Ha! Thanks, both. I understand accuracy and precision. I just meant I didn't understand the purpose of pointing that out now. Turns out there is something off with the reagents between packages, but I'm not sure there is a more precise test than Hanna.
 
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