Apogee Instruments MQ-650

The MQ-650 ePAR meter is designed for underwater PAR measurements (400-750 nm) and already applies a sensor immersion correction factor to the meter data via firmware.

The meter provides excellent measurements under all light sources, including LED. The meter consists of a waterproof quantum sensor connected by a waterproof cable to a handheld meter.
The waterproof sensor contains a silicon photodiode with blue gain and custom optical filters with a rugged anodized aluminum body with an acrylic diffuser.
The underwater quantum sensor is typically used in marine aquariums where corals are grown.

The handheld meter is not waterproof, only the sensor and cable are waterproof.