Nitrates can be tested for in a variety of ways. Most tests involve a colormetric change. Some kits measure this change through electronic means, others use a simple color wheel comparator.

Listed below are the instructions for measuring nitrate (NO₃^-) levels between 0-50 mg/l using a Model NI-11 test kit manufactured by Hach Co.

1. Rinse a color viewing tube several times with the water to be tested; then fill to the 5-ml mark.

2. Open one NitraVer 5 Nitrate Reagent packet. Add the contents of the packet to the tube containing the water sample to be tested. Stopper the tube and shake it vigorously for exactly one minute. An amber color will develop if nitrate is present.

3. Allow the prepared sample to set undisturbed for one minute.

4. Place the amber colored disk into the black comparator box.

5. After the sample has set undisturbed for one minute, place the tube into the top right opening of the black comparator box.

6. Fill the other viewing tube to the 5-ml mark with some of the original water sample and place it into the top left opening of the black comparator box.

7. Hold the comparator box up to a light source and view through the openings in the front. (Use a white sheet of paper for a background.) Rotate the color disk in the comparator box until the two colors match. Read the mg/l nitrate nitrogen (N) through the scale window.

8. Test results can be converted from mg/l nitrate nitrogen (N) to mg/l nitrate (NO₃^-) by multiplying the scale reading by 4.4.

9. When finished, pour the used chemicals into the waste collection container. Clean the equipment and return it to its proper place.