This TriOxmatic® series (ECDO) are electrochemical sensors that are commonly used for water and waste water operations. With this device, the O2 is diffused through the membrane of the TriOxmatic sensor. Oxygen is converted during a chemical reaction through an electrolyte, which enables the current to be measured. The tool's electrical current correlates to the oxygen concentration. Flow, continuous exchange of electrolytes, and clean membrane aids in providing accurate results from the apparatus. This tool also features low maximum errors of 15 of the measured value.