The Auto-Chem sulfite system employs a unique gas-phase method that continuously monitors sulfite without contact between the sensor and the water sample. This air-stripping method works by mixing the sample with an acidic solution converting the sample into a sulfur dioxide gas; this gas is then stripped from the sample. Using the special sulfur dioxide gas sensor, a gas-conditioning module prepares the gas sample for measurement. Sensor signals are then amplified and displayed on a large-format, backlit LCD display in the system’s electronic unit.