All Apogee Underwater Quantum Meters and Sensors models (MQ-210 and -510, and SQ-420 and -520) automatically correct for the immersion effect or have an immersion setting, allowing the user to make excellent underwater measurements right out of the box. Sensors feature a waterproof sensor head that is potted solid for a complete seal and to ensure it has no hollow cavities for water to penetrate and cause measurement errors.

The MQ-210 and -510 meters record up to 99 manual measurements. In logging mode the meter will make a measurement every 30 seconds. Every 30 minutes the meter will average the sixty, 30-second measurements and record the averaged value. The meter can store up to 99 averages. The SQ-420 and -520 USB sensors have internal memory capable of storing 10,000 user-specified periodic measurements that can be downloaded to a computer.

PPFD measurements over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under canopy (transmitted) PPFD measurements in the same environments. Quantum sensors are also used to measure PPFD in aquatic environments, including salt water aquariums where corals are grown.