@CaseyWagner

Do you mean you did an Arch Linux install just to get this working, and gave up on Windows?

Please help us, Jo!

I am using the precompiled Windows app, version 4 (v5 crashes). Under Options/Sample Units, the app has selected uM, and you may not select PPM.

https://i.imgur.com/b3TJHZ9.png

However, when you take nitrate measurements, the value returned is reasonable for PPM. As I understand the conversion between uM and PPM for nitrate, the app cannot be returning uM. For example, my API nitrate test kit shows a color that looks about like 20 PPM per the color card, and the colorimeter reports it as 17.5 PPM. The number would be very different in uM.

Can you clarify this? If it is a display issue, cool, I just need to know how to interpret the number I am getting.

When I got my colorimeter, the v5 exe was crashing on Windows 10, so we had to use v4.

Will there be another precompiled executable?

We are advised to make our own nitrate calibration samples, starting with a stock solution. But measuring weight and volume at home is pretty easy, so is it possible to make our own 1000 ppm standard instead of buying an expensive and perishable stock solution?

This guide SEEMS to be describing creating the same kind of solution as the Labtech standard we are advised to purchase, where 1 mL contains 1 mg nitrogen.

http://www.globe.ee/TeacherGuide/hydrology/protocols/fieldguides/hydro_fg_1000ppmN.pdf

Replying to myself here. I took another look at the instructions:

http://public.iorodeo.com/docs/nitrate/api.html

Here is the part I missed the first time: Before measuring blank the colorimeter against water or a distilled water sample developed with API reagent as described below

This must be the sample that the "Calibrate" button requires.

What I don't understand is why this sample is not handled by the calibration curve. It includes a 0 PPM sample. I guess the intent of the blanking step is to see what the current state of the LED and sensor is, so it can apply that correction to the curve?

This does mean that each test would have to use 2x the reagent, which is unfortunate... but worth it if I can get a number I can trust.

I got the colorimeter kit because I am interested in the aquarium tests. I think I am almost there but am unsure how to operate the Measurement program.

I have loaded the sample API nitrate calibration data, made a plot with curve fit, saved the test solution, selected that test solution in Measurement, but am now unclear on exactly how to measure my sample. Oh, I am using the .exe v04, as v05 is crashing on Windows 10.

In the Measurement program I am unable to measure unless I first click Calibrate. But what am I calibrating with? Plain water? (And why is that necessary if we have a calibration curve?)

After calibrating with water, I mashed Measure and my API nitrate test sample gave me values of about 25 uM.

I was expecting to see approximately 20 PPM based on the color chart, but in the Measurement program I am unable to change from uM to PPM in the menu. Both are dimmed out.

But, since I got a value that looks about right for PPM, I wonder if there is a labeling bug and these are PPM values, even if they are labeled uM?

OK, so let's assume we are looking at uM NO3. You can convert micromoles per liter NO3 to PPM if you divide by 16. 25 uM would be about 1.6 PPM, and based on the color of the kit, that cannot be right. It really does need to be approximately 20 PPM.

So right now it looks like you have to calibrate with water, and you will get results in PPM even if the menu is stuck on uM.

Assuming I was correct to calibrate with water, and I actually measuring 25 PPM NO3, this is super duper cool and I love this thing.

Can anyone straighten me out?

I just got started and got bit by this too. Do you have a new exe yet?

I will install Python and figure out the dependencies if I have to.

I just assembled my kit and achieved "first light" on Windows 10. I learned a couple of things that might help others who are just getting started

#1 You don't have to install Pyton, there is an executable
Do not overlook the precompiled binary if you want to get going quickly.
https://bitbucket.org/iorodeo/colorimeter/downloads/

#2 If your Windows exe doesn't seem to be working right check the scaling settings
I fired up the app and the window looked like this, and I couldn't get it to do anything.

I found that the window was mangled because the exe was not handling my 4k display well. I fixed this by turning on the Windows "High DPI Scaling Override."

• Right-click and do Properties on the exe
• Hit the Compatibility tab
• Hit the Change High DPI settings button
• Check High DPI scaling override
• In the menu, select System (Enhanced)
• OK and Apply your way out

Once I did that and restarted, the app looked like this, and I was able to start the Basic program and calibrate with water.

I hope this helps someone!