1. Fill the measuring syringe to the 5ml mark with the water sample to be tested. The bottom of the curved surface or meniscus should be exactly level with the 5 ml mark. * 2. Empty the contents of the measuring syringe into he mixing bottle. * 3. Add 6 drops of Nitrite Indicator Solution and mix. -If the water turns Blue, no Nitrite is present. Test = 0 ppm -If the water turns Red, Nitrite is present and the test should be continued. * 4. Add NT-2NA Ceric Sulfate Titrating Solution drop wise, shaking the bottle between each drop, counting the drops until the water sample turns Blue or Blueish Green and remains Blue or Blue-Green for 15 seconds. This is the end point. * 5. The "NaNO2" reading of the water in ppm (mg/L) is equal to the number of drops used times the number factor shown on the bottle of the titrant.