Cleanliness and following instructions are important factors in testing equipment maintenance and procedures:
• Keep the reagent bottles, containers, vials, test tubes, comparators, dip cells, and hands clean and dry.
• Remove any spills and drips.
• Cross contamination between reagents caused by sloppy technique can cause problems before testing is even started.
• Get a fresh water sample in a clean container.
• Rinse the sample container with the water and get a sample from well below the water surface.
• Avoid sampling near water inlets and returns.
• Never test the water immediately after shocking or other chemical addition.
• When testing, follow the instructions carefully, including any specified waiting times.
• If adding drops of a reagent, hold the bottle vertically to get even sized drops.
• If doing a visual colorimetric determination (a color match), use a white or neutral color for a background. Use indirect light with your back to the sun.
• If using a colorimeter, run the test in the shade if possible.
• Avoid testing at the very top or the very bottom of a test range. These portions of the range often have poor accuracy.
• After testing, clean and rinse equipment and allow it to air dry.
• Store the test kit and reagents in a cool dry place.
• Periodically, test your kits against known reference standards recommended by the manufacturer.