Dissolved Oxygen Meter: What It Is and How It Works

A dissolved oxygen meter is a scientific device used to measure the amount of gaseous oxygen dissolved in water or other liquids.

How It Works

• Optical Sensors: Use luminescent light. Oxygen quenches the light; the meter measures this change to find the oxygen level. They need little maintenance and no constant water stirring.
• Electrochemical Sensors: Use a membrane and an electrolyte solution (polarographic or galvanic). Oxygen passing through the membrane creates an electrical current that the meter reads.

Key Measurements

• mg/L or ppm: Shows the absolute weight of oxygen per liter of water.
• % Saturation: Shows the ratio of oxygen relative to the maximum possible amount at that specific temperature and pressure.
• Temperature: Most meters track temperature simultaneously because water temperature changes how much oxygen it can hold.

Common Uses

• Aquaculture: Monitoring fish farms to ensure fish have enough oxygen to breathe.
• Wastewater Treatment: Checking aeration tank efficiency.
• Environmental Testing: Testing lakes, rivers, and streams for ecological health.