The Orion Star RDO series of optical dissolved oxygen meters is claimed to ensure accuracy with the least amount of maintenance.
There are no membranes and sensor maintenance involves a simple, once-a-year cap replacement.
The rugged design is available in a variety of handheld options from single to multiparameter meters. The meters are suitable for effluent, aeration basins and also influent, as the sensor is not affected by colour and turbidity.