The measurement principle is based on the UV-light-absorption spectrum of ammoniac gas NH3 in equilibrium with dissolved ammonia (ammonium or NH4+) in the water sample. - Measurement time: 5 minutes - Interference with color or turbidity: no - Standard solution: no need - Expensive or specific reagents: no - Periodic change of electrode or lamp or parts: no - Maintenance: low - Filtering: no need - Automatic cleaning system: yes - Operating cost: low - Size: compact - Weight: 15-25 kg approx. - Transportable by car or passenger plane: yes - Installation time: few minutes