- The test strips are meant to detect ammonia and ammonium in water, but not combined ammonia compounds like chloramines.
- The test strip uses two pads in the test pad “sandwich” – the first pad creates an alkaline environment (pH > 11) which converts all of the ammonia/ammonium present to ammonia. The second pad employs a hydrophobic material and indicators to detect the ammonia present.
- The color chart is ppm as ammonia-nitrogen, not ammonia. There is sometimes confusion when comparing competing strips – some measure as ammonia-nitrogen (NH3-N), while others measure as ammonia (NH3). The 100 ppm as ammonia-nitrate is equivalent to 122 ppm as ammonia.
- The color charts were developed by creating ammonia standards from ammonium chloride (ACS grade). 0.19 grams is dissolved in 500 mLs of ammonia-free water. This is 100 ppm as ammonia-nitrogen. Serial dilutions produce the other standards.