ORIGINAL SUNLIGHT UNDERWATER QUANTUM METER - Designed by world-renowned crop physiologist, Bruce Bugbee, PhD, the Apogee MQ-210X "original" quantum meter features Apogee's older and more economical photodetector that is excellent for measuring photosynthetically active radiation (PAR) accurately under sunlight, metal halide, and high-pressure sodium lights. For measuring other light sources, including LEDs, we recommend using our newer full-spectrum or ePAR sensors.

MEASURING PAR IS CRITICAL - Measuring the PAR levels of your grow lights is one of the most critical measurements in the precision growing of plants and other photosynthetic organisms in greenhouses, growth chambers, farms, gardens, and aquariums. Our underwater original quantum meters are specifically designed to measure the intensity of sunlight, MH, and HPS lights underwater for biological, chemical, and physical processes in natural waters and aquariums.

UNDERWATER ACCURACY - Underwater PAR measurements can read low when a sensor is calibrated for air. This applies an immersion effect correction factor to get accurate measurements underwater by combining the intensity of all photons between 400-700 nm under sunlight, MH, and HPS lights to give a single PAR reading within 5 % uncertainty. Unlike hobby-grade PAR meters that may be accurate when new, but quickly lose calibration, our meters are stable with a drift rate of less than 2% per year.

FOR SCIENTISTS & SERIOUS GROWERS - Unlike cheaper LUX or footcandle sensors which are sometimes marketed as grow light meters, but are meant for measuring light for human vision, our meters feature a laboratory-grade photosynthetic photon flux density (PPFD) optical detector precisely calibrated to measure the light intensity in µmol m^-2 s^-1 of the specific color wavelengths emitted by sunlight, MH, and HPS lights that are used by plants for photosynthesis.

RUGGED & EASY TO USE - Quantum sensor head is machined aluminum and potted solid with epoxy for years of use in harsh environments, especially in saltwater or freshwater. The handheld meter is attached by a cable and displays real-time readings, records samples, and logs average intensity and daily light integral (DLI) measurements. Unlike the sensor head, the handheld meter is not waterproof.

THREE MEASUREMENT MODES - The meter has a spot measurement, sample, and log mode and will record an integrated daily total in mol m^-2 s^-1. Sample mode will record up to 99 manual measurements and log mode will power the meter on and 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, up to 99 averages. Once full, it will overwrite the oldest measurements with new ones. A daily light integral will be recorded from the 48 averaged measurements for a day’s worth of readings and is downloadable via Apogee AC-100 cable and used with the included ApogeeAMS software.

MADE IN THE USA - All meters are designed, built, and calibrated at our headquarters in Logan, Utah, USA. Apogee Instruments has been creating research-grade instruments for scientists and serious growers for over 25 years. All meters are backed by our industry leading four-year warranty and supported by our world-class, US-based customer support team.

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