Repurpose Hannah copper checker?
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Jay Hemdal
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Interesting question!
The Hanna reagent for copper is the bicinchoninate method. It makes a purple color in the sample. The photocell is probably tuned to that wavelength. If you had another color change test of a similar color, you could make a standard curve using spiked samples and then use that for testing unknown samples. I did that once with the API copper reagent - it is almost impossible to read that test. I made a standard curve of known concentrations of copper, used the reagent and a spectrophotometer, and was able to use the API reagents much more easily.
Jay
The Hanna reagent for copper is the bicinchoninate method. It makes a purple color in the sample. The photocell is probably tuned to that wavelength. If you had another color change test of a similar color, you could make a standard curve using spiked samples and then use that for testing unknown samples. I did that once with the API copper reagent - it is almost impossible to read that test. I made a standard curve of known concentrations of copper, used the reagent and a spectrophotometer, and was able to use the API reagents much more easily.
Jay
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Yes. The LED is 575 nm and will be potentially useful for nitrate, nitrite, phosphate and possibly ammonia tests. When in doubt, just try it.
The catch is the light absorbance to which the Checker is adjusted to. If the copper test is a deep color test, it might be useful for nitrate testing but not a replacement for the ULR phosphate Checker. Again, you just have to try it.
Each test you run will need to be calibrated against a standard so you can convert the Checker reading to ppm for that analyte.
Happy to help. I and @taricha have repurposed Checkers many times.
Red2143
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Very interesting. I'd be interested in using it for nitrate. Has anyone specifically had success before I go out and buy a box of reagent?
Copper is 575nm
Nitrate 525nm
Alkalinity 610nm
Seems very close
Copper is 575nm
Nitrate 525nm
Alkalinity 610nm
Seems very close
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Red2143
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High range hi702
but does the cell look for an actual color or how much light can pass through the solution?
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It simply shines a fixed-color LED at a photodetector. Thus it measures the absorbance of that specific color of light. It has no idea what the visual color of the solution is.
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Okay, I will take a look at what hanna High Range NO3 packets register on my LR Cu checker and can estimate a range that the HR Cu could cover (it'll go about 5x higher than the LR Cu checker). I'm guessing it'll cover at least half the zero to 75 ppm range.
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The answer is kinda, but not a good idea to use the hanna HR NO3 packets in the Cu checker. And there's a better solution available.
Here's calibration data for my tank water spiked with a few NO3 levels and run the hanna HR NO3 chemistry on it, and put it in either the hanna HR NO3 checker or the LR Copper checker.
and while it looks good....
This is not a good wavelength for this test.
The LED wavelength for the Cu checkers is going to be out around 575nm which means you are measuring waaay on the edge ot the peak. Measuring that far out means that small differences (one LED's checker vs the next, one reagent lot vs another) will mess up the result a lot.
But, you should instead run a Red Sea NO3 test in the checker.
Red Sea NO3 color is much closer to the right wavelength for the Cu checker.
This is the spectrum of the Red Sea NO3.... measured by @Rick Mathew here
as you can see, the 575nm hits very near the fat part of the peak and is a much better pair to use.
In fact, it looks like Rick may already have done this years ago.
This is regression data for measuring Red Sea NO3 with a hanna HR copper checker. (different model Cu checker, but I'll bet it works the same.)
@Red2143 you may give that a try.
Here's calibration data for my tank water spiked with a few NO3 levels and run the hanna HR NO3 chemistry on it, and put it in either the hanna HR NO3 checker or the LR Copper checker.
| Total ppm NO3 stock | HR NO3 checker (ppm) | LR Cu checker (ppb) |
| 0.0 | 0.5 | 51 |
| 2.1 | 3.0 | 119 |
| 5.1 | 6.4 | 207 |
| 10.3 | 11.4 | 423 |
| 20.5 | 22.3 | 748 |
and while it looks good....
This is not a good wavelength for this test.
The LED wavelength for the Cu checkers is going to be out around 575nm which means you are measuring waaay on the edge ot the peak. Measuring that far out means that small differences (one LED's checker vs the next, one reagent lot vs another) will mess up the result a lot.
But, you should instead run a Red Sea NO3 test in the checker.
Red Sea NO3 color is much closer to the right wavelength for the Cu checker.
This is the spectrum of the Red Sea NO3.... measured by @Rick Mathew here
as you can see, the 575nm hits very near the fat part of the peak and is a much better pair to use.
In fact, it looks like Rick may already have done this years ago.
This is regression data for measuring Red Sea NO3 with a hanna HR copper checker. (different model Cu checker, but I'll bet it works the same.)
Rick's approximate regression is about [NO3 ppm] = 6.0 x [Cu checker ppm].
@Red2143 you may give that a try.
Red2143
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Thank you very much. Non scientist but was able to understand the clear explanation. Can you explain the wavelength absorbtion test and how that's done?
Is api reagent similar to red sea? Looks like one is pink and the other yellow to red
Is api reagent similar to red sea? Looks like one is pink and the other yellow to red
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Yes.
A light is shined through a clear water blank and then the colored solution is put in place of the blank. The instrument (spectrometer) measures how much each wavelength of light is absorbed by the colored solution compared to the clear water. High absorbance at a particular wavelength means that it absorbs that color of light strongly.
( measuring a solution with a spectrometer that gives you the absorbance at all wavelengths is a good way to find out which particular wavelength LED checkers will be good for a particular color solution.)
The yellow in API is likely a constant that can be avoided or subtracted out mathematically, and I'm guessing the color formation happens at around the same wavelength as red sea. But I will defer to @Dan_P on that one. I haven't used API nitrate test.
Malcontent
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The API nitrate test likely uses chromotropic acid as its azo component which is yellow-red. API nitrite and Hanna nitrate and all other purple-pink nitrite/nitrate tests likely use N-(1-naphthyl)ethylenediamine.
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Well, if you have checkers for high and low amounts of color at the 4 different hanna wavelengths: 470, 525, 575, and 610nm then you could measure almost any chemical test end product.
And if you can make accurate stocks and plot regression equations, then sure!
(But that would be a bunch of checkers)
Sean Clark
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So, you're saying there's a chance...
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For API nitrate, I use the Hanna HR Marine Nitrate Checker for the ability to cover a large range in nitrate. The phosphate Checkers will work but for a narrower range.
Also, just because the Checker might not have an LED that is complimentary to the test color, the test color can have a very broad visible spectrum that can overlap the Checker wavelength. This means it can work, maybe the sensitivity will be lower.
Hopefully, this makes some sense. If not, I will try again.
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