Our dissolved oxygen probes feature optical measurement using the luminescence method and are commonly used in wastewater, sludge treatment, fish farming and biological treatments. Dissolved oxygen (DO) is a measure of the concentration of free oxygen molecules present in water. The concentration of DO is an important indicator of the health of an aquatic ecosystem and fundamental for almost all forms of life. Dissolved oxygen in water comes from two main sources: the atmosphere and photosynthesis. The main factors that affect its concentration are temperature, altitude, salinity and the water’s degree of stagnation or movement.