|Interference may be caused by:
||Bromine, Chlorine, Ozone, oxidised forms of chromium and manganese. Alkalinity above 250 mg/L and acidity above 150 mg/L as CaCO3 require neutralisation since the colour could instantly fade. To resolve this, neutralise the sample with diluted HCl or NaOH. In case of water with hardness greater than 500 mg/L CaCO3, shake the sample for approximately 2 minute after adding the reagent. Alternatively, wait for 2 minutes and 30 seconds then just press READ/TIMER. In both cases, the lamp, cuvette and detector icons will appear on the display, depending on the measurement phase.