Question on $20 Hach test kit

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Prolific Poster
Apr 24, 2005
I cheaped out and bought the inexpensive $20 Hach NO3 test kit instead of the more expensive Hach or LaMotte kits and have been using it for a few months. It tests accurately against a fixed sample and seems to test consistent with what I'm dosing. The tube is kind of cheap with pretty limited color gradation but I like that the colors are built into the tube for ease of comparison. I also like that what I'm adding comes in premixed packets so I don't have to worry about getting the amount wrong. It uses a "cadmium reduction" method whatever that means and only takes 2 minutes to use.

Anyway, Tom do you or anyone else have any experience or feedback with this type of kit? Is this a reasonable alternative to the $50 kits or am I kidding myself here? It certainly seems better than the $5 AP kit I was using which was testing double the NO3 amount when tested against a fixed solution.

If anyone's interested in looking at the kit it's at "" enter 1403700 as product # under advanced search.

Thanks, Bill

I know, I know, I probably don't need it anyway but it seems to be the one test I like to use as a reference point.

Tom Barr

Staff member
Jan 23, 2005
Re: Question on $20 Hach test kit

Let's get one thing straight, I've never been anti test kit.

I have been seriously questioning the use of cheap test kits and they are huge source of error for many.........................

There is a distinct difference.

If you know how to make a reference sample and a series of them, then graph that and get a good R^2 value, then you can be fairly confident.

Some just assume other folk's expeirneces are good, and they just go wiht that, that is not how to do this!

You need 3 soluitions. say 1ppm, 5ppm, and 20ppm, 40ppm would be nice also. Make the 40ppm first the dilute to make the others.

Be very careful, use the most accurate bscale and milliliter measuring device you can get.

I use 100ml volumetric flask and a scale that is accurate to less than a milligram.

From what you have said, it seems the Hach kit is pretty good for a mid priced test kit.

I have not used it nor know the model number etc.

So you have to have pretty accurate standards and methods to measure it.
I think some get sort of close, but to date, I've not seem anyone offer up an R^2 vaue when calibrating.
It does add a level of confimation.

I'll detail this out later.

Tom Barr