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Enabling better global research outcomes in soil, plant & environmental monitoring.

MQ-210 Underwater Quantum Meter

The MQ-210 quantum meter is designed for underwater PAR measurements and already applies the sensor's immersion effect correction factor to the meter readings through firmware. The meter consists of a waterproof quantum sensor attached via waterproof cable to a handheld meter. The waterproof sensor incorporates a blue-enhanced silicon photodiode and custom optical filters with a rugged, anodised aluminium body with acrylic diffuser. The underwater quantum sensor is typically used in salt water aquariums where corals are grown.

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

Ready for Underwater Use
The MQ-210 has the immersion effect correction factor pre-programmed in the meter firmware, allowing you to make excellent underwater measurements right out of the box.

Waterproof Sensor
The meter features 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.

Spectral Response
The original Apogee quantum sensor works well for the broadband radiation sources (sen, and high pressure sodium, metal halide, cool white fluorescent lamps). The sensor has a spectral range of 410 to 655nm.

Accurate, Stable Measurements
Calibration in controlled laboratory conditions is traceable to a NIST lamp. Quantum sensors are cosine-corrected, with directional errors less than ± 5% at a solar zenith angle of 75°. Long-term non-stability determined from multiple replicate quantum sensors in accelerated aging tests and field conditions is less than 2% per year.

Datalogging Capabilities
The meter records 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.

Calibration Uncertainty: ± 5%
Measurement Repeatability: Less than 1%
Long-term Drift (Non-Stability): Less than 2% per year
Response Time: Less than 1 ms
Field of View: 180°
Spectral Range: 410 to 655 nm
Directional Cosine Response: ± 5% at 75° zenith angle
Temperature Response: 0.06 ± 0.06% per °C
Operating Environment: 0 to 50°C; less than 90% non-condensing relative humidity up to 30°C; less than 70% non-condensing relative humidity from 30 to 50°C; separate sensor can be submerged in water up to depths of 30m
Meter Dimensions: 126 mm length; 70 mm width; 24 mm height
Sensor Dimensions: 24 mm diameter; 28 mm height
Mass: 180g
Cable: 2m of two conductor, shielded, twisted-pair wire; additional cable available; santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions)

MQ-210 Dimensions

Calibration Traceability

Apogee Instruments MQ series quantum sensors are calibrated through side-by-side comparison to the mean of four Apogee model SQ-110 or SQ-120 transfer standard quantum sensors under high output T5 cool white fluorescent lamps. The transfer standard quantum sensors are calibrated through side-by-side comparison to the mean of at least three LI-COR model LI-190R reference quantum sensors under high output T5 cool white fluorescent lamps. The reference quantum sensors are recalibrated on a biannual schedule with a LI-COR model 1800-02 and quartz halogen lamp traceable to the National Institute of Standards and Technology (NIST).

Cosine Response

MQ-210 G1

Mean cosine response of twenty-three MQ-210 quantum sensors (error bars represent two standard deviations above and below mean).
Cosine response measurements were made by direct side-by-side comparison to the mean of four reference thermopile pyranometers, with solar zenith angle-dependent factors applied to convert total shortwave radiation to PPFD. Blue points represent the AM response and red points represent the PM response.

Spectral Response

MQ-210 G2

Mean spectral response of six MQ-210 quantum sensors (error bars represent two standard deviations above and below mean) compared to PPFD weighting function. Spectral response measurements were made at 10 nm increments across a wavelength of 300 to 800 nm in a monochromator with an attached electric light source. Measured spectral data from each quantum sensor were normalised by the measured spectral response of the monochromator/electric light combination, which was measured with a spectroradiometer.

Temperature Response

MQ-210 G3

Mean temperature response of eight MQ-210 quantum sensors (errors bars represent two standard deviations above and below mean).
Temperature response measurements were made at 10°C intervals across a temperature range of approximately -10 to 40°C in a temperature controlled chamber under a fixed, broad spectrum, electric lamp. At each temperature set point, a spectroradiometer was used to measure light intensity from the lamp and all quantum sensors were compared to the spectroradiometer. The spectroradiometer was mounted external to the temperature control chamber and remained at room temperature during the experiment.