MQ-650: ePAR Underwater Meter

The MQ-650 ePAR meter is designed for underwater extended PAR measurements (400-750 nm) and already applies the sensor's immersion effect correction factor to the meter readings through

  • Product Name:MQ-650: ePAR Underwater Meter
  • Item No.:MQ-650
  • Manufacturers:Apogee
  • Country of Origin:USA

The MQ-650 ePAR meter is designed for underwater extended PAR measurements (400-750 nm) and already applies the sensor's immersion effect correction factor to the meter readings through firmware. The meter provides excellent measurements under all light sources, including LEDs. 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, anodized aluminum 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. 

The meter has a sample and log mode, and will record an integrated daily total in mol m-2 d-1. Sample mode will record up to 99 manual measurements. Log mode will power the meter on/off to make a measurement every 30 seconds. Every 30 minutes the meter will average the sixty 30 second measurements and record the averaged value to memory. The meter can store up to 99 averages, once full it will start to overwrite the oldest measurement with new ones. An integrated daily total will be recorded from the 48 averaged measurements (making a 24 hr period). Sample and log measurements can be reviewed on the LCD display or by downloading the data to a computer, however, the integrated daily total can only be viewed by downloading the data to a computer. Downloading data to a computer requires the AC-100 communication cable (a standard USB cable will not work) and ApogeeAMS software. 


Calibration Uncertainty± 5 %Measurement Range0 to 4000 µmol mˉ² sˉ¹Measurement RepeatabilityLess than 0.05 %Long-term Drift (Non-stability)Less than 2 % per yearNon-linearityLess than 1 % (up to 4000 µmol mˉ² sˉ¹)Response TimeLess than 1 msField of View180˚Spectral Range400 to 750 nm ± 5 nm ( wavelengths where response is greater than 50 %)Directional (Cosine) ErrorLess than ± 5 % at 75˚ zenith angle and 10 % from 412 to 682 nm ± 5 nmAzimuth ErrorLess than 0.5 %Tilt ErrorLess than 0.5 %Temperature Response-0.11 ± 0.04 % Cˉ¹Uncertainty in Daily TotalsLess than 5 %DetectorBlue-enhanced silicon photodiodeHousingAnodized aluminum body with acrylic diffuserIP RatingIP68Operating Environment0 to 50 C, less than 90 % non-condesing relative humidity up to 30 C, less than 70 % non-condensing relative humidity from 30 to 50 C; separate sensors can be submerged in water up to depths of 30 mMeter Dimensions126 mm length, 70 mm width, 24 mm eightSensor Dimensions30.5 mm diameter, 37 mm heightMass180 gCable2 m of two conductor, shielded, twisted-pair wire; additional cable available; TPR jacketWarranty4 years against defects in materials and workmanshipManufacturedMade in the USA