• Ensure that the test tube is clean before use.
• Clean the tube directly after use.
• Take the volume of the water sample as precisely as possible.
• Keep the dripping bottle perfectly vertical during dropping.
• Take care that no air bubbles are included in the drops.
1. Take a water sample of 5 ml.
2. Add 5 drops of NO2 test fluid.
3. Shake well.
4. Wait 5 minutes.
5. Determine the NO2 -value using the included colour chart. An optimal nitrite level in all kinds of water is simply 0 mg/l. When the nitrite level is 0.5 mg/l or higher, it means that there are not enough bacteria present. In this case we recommend to add Colombo marine bacto.