Tech Tips

Yellow Reaction for Nitrate

Question: Why do your LaMotte Nitrate TesTabs® sometimes turn yellow instead of shades of pink?

Answer: From Charlie in Technical Service - The Nitrate (Wide Range) TesTabs® are sensitive to heat and moisture. Best results are obtained if the tablets are kept at room temperature. Exposure to high heat will degrade them before their expiration dates. Pink spots on TesTabs® signify exposure to moisture and invalidate the results. A sample which is negative (0 ppm) for nitrate may range from colorless to yellow due to some unknown factor/color contained in the sample.