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SQ-120: Electric Calibration Quantum Sensor

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Product Description

The SQ-120 is a self-powered quantum sensor that measures photosynthetically active radiation and is calibrated for use with electric lights. The sensor housing design features a fully potted, domed-shaped head making the sensor fully weatherproof and self-cleaning. Photosynthetically active radiation (PAR), or photosynthetic photon flux (PPF), is the wavelength range from 400 to 700 nanometers and is strongly correlated with plant growth. Gardeners, greenhouse managers, growth chamber users and salt-water aquarists measure PAR to insure optimal specimen health.

Owner’s Manuals

Spec Sheet: SQ Series

Owner's Manual: SQ Series


0.2 mV per µmol m-2 s-1
Calibration Factor
5.0 µmol m-2 s-1 per mV (reciprocal of sensitivity)
Calibration Uncertainty
± 5%
Measurement Repeatability
< 1 %
Non-stability (Long-term Drift)
< 2 % per year
< 1 % (up to 4000 µmol m-2 s-1 )
Response Time
< 1 ms
Field of View
Spectral Range
410 nm to 655 nm (wavelengths where response is greater than 50 % of maximum)
Response Time
± 5 % at 75° zenith angle
Temperature Response
0.06 ± 0.06 % per C
Operating Environment
-40 to 70 C, 0 to 100 % relative humidity, Can be submerged in water up to depths of 30 m
2.4 cm diameter and 2.8 cm height
90 g (with 5 m of lead wire)
5 m of shielded, twisted-pair wire. Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions). Pigtail lead wires
4 years

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Product Reviews

  1. my PAR probe used for reef tank light measurement at LEDs 5 Star Review

    Posted by on 20th Dec 2012

    OK, you can't compare one kind of light to another with any one measurement system. Each photo/filter cell type will measure different aspects of light, and every light source type projects different aspects. That said PAR is as close as we can get for an affordable photo processes measuring instrument for light used by plants and animals. Then when you can buy just the PAR probe and splice it to your DVM and use the vM DC scale, you win again. When the instructions even allow you to do that and give you the multiplying factor, that kicks ass. I mounted my probe with the supplied and installed plastic screw on the back to a small piece of acrylic with a plastic rod to reach in and take PAR readings anywhere in a reef tank. I take it with me and take readings at the stores when I purchase corals so I can take them home and place them in my tank at a similar PAR read location. Happy? .. yes Happy. Works perfectly. Highly recommended.