SQ-520 Full Spectrum Smart Quantum LED PAR Sensor

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$364.00 $455.00

Discontinued by Bulk Reef Supply
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Increased Accuracy for LED Lighting Measurements!

The Smart Quantum SQ-520 PAR Sensor is a USB powered sensor that will hook up to any PC or MAC allowing you to use your personal computer instead of an expensive dedicated monitor with the included 15 foot long USB cable. Hooking a sensor up directly to your computer allows you to easily log readings within the Apogee software or any application of your choice.


For Apogee Underwater PAR Measurement Correction Factors and Calculator - Click here


The SQ-520 Par Sensor has been specifically designed to give reliable and repeatable readings under LED lighting. With an increased spectral range, and larger sensing optic you will get more precise readings with all types of lighting systems. If you do not have a computer near your tank, don't worry, the SQ-520 can store up to 10,000 measurements internally and viewed later when powered by a stand-alone 5v USB power adapter like a battery pack or wall adapter.


Apogee has calibrated the SQ-520 with electronic lights making them perfect for any type of aquarium lighting. Calibration will be stored within the firmware of the sensor. The sensor has a housing designed to be fully weather-proof and self-cleaning allowing years of service with minimal maintenance.


No more days of looking and guessing how much light is being put into your tank. Apogee is the leader in radiation sensing devices and recently introduced the SQ-520 USB Powered Quantum PAR Sensor. With the easy to use software that can be downloaded, just as long as you have an open USB port on your Windows or MAC computer simply plug the USB sensor in, download the software and you are off and running


PAR (photosynthetic active radiation) is the easiest way to measure the available light for corals consume and use for photosynthesis. With LED lights giving more and more control to the consumer the best thing is a PAR meter that is affordable and simple to use. With PAR readings you can monitor light degradation, clarity of the water, and intensity of the lighting schedule. Most LED lights out on the market today have more power than what your corals can take and will quickly bleach out from too much light. By having a PAR meter to monitor the light intensity you will have tangible numbers to go off of, instead of just guessing.


We personally like inputting all of our reading into a spreadsheet to make a chart of light output and overlay the readings on a photo as well. Having a picture with your tanks PAR levels is very handy to have when placing new corals in your tank.


  • Resolution - 0.1 µmol m-2 s-1
  • Calibration Factor - custom for each sensor and stored in the firmware
  • Calibration Uncertainty - ± 5 %
  • Measurement Repeatability - less than 1 %
  • Response Time - software updates every second
  • Field of View - 180°
  • Spectral Range - 389 nm to 692 nm (wavelengths where response is greater than 50% of maximum)
  • Dimensions - 2.4 cm diameter and 3.7 cm height
  • USB Cable - 4.6 m (15 ft)
  • Current Draw (when Logging) - 5.1 mA
  • Warranty - 4 years


Software Download

Spec Sheet SQ-520 Spec Sheet

Manual SQ-520 Owners Manual


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Product Questions

I see that this device can be plugged into a wall outlet and will take/store readings without a computer attached. Then the readings can be downloaded later, which allows you to use the device without having a computer right next to the tank.

Could you please explain how you could take several readings this way (without a display) and then download them from the meter to your computer without mixing up which reading is from which parts of the tank?

As a work-around, I suspect that you could position the meter, plug it in, take a single reading, and then immediately go to your computer to retrieve the reading, but I am wondering if there is an easier way to manage readings without having a computer attached right next to your tank.
Question by: Andrew Bouwma on Feb 16, 2017, 10:35 AM
Hey there,
When using an independent power source for data sampling, you would first want to connect the sensor to your computer to set the sampling/logging parameters. You can set the sampling and/or logging interval from 1 second to 1 day. The sample interval must evenly divide into the logging interval (so, 1 minute samples with 5 minute logs is fine, but 2 minute samples with 5 minute logs is not). The logged info is an average of any samples taken between logs.

Hope this helps! Have a great day!
Answer by: Zack on Feb 17, 2017, 3:02 PM