Lab-Grade Instruments Designed Specifically For Growers
Lab-Grade Instruments Designed Specifically For Growers
Thank you for choosing the Apera GroStar™ GS3 Premium EC Pen Tester. This premium pen has been designed
specifically for the horticultural market. Since 1991, Apera instruments has been dedicated to providing hi-tech,
accurate, lab-grade instruments and sensors. GroStar's intelligent design reduces the guesswork so you can easily
manage your crops success.
• Premium titanium alloy conductivity probe measures EC, ppm (500/700) all-in-one unit with minimal maintenance.
• Easy to use design and quick 1-point calibration adjustment.
• 3-Color backlit LCD screen gives you clear readings in different modes even in dark enviroment.
• Durable structure, IP67 waterproof rating, powered by AAA batteries.
• The probe is replaceable, so you don't have to discard the entire pen when the probe reaches its end of life.
Color LCD Screen
stands for stabilized reading
Probe Cap
M stands for successful calibration:
M is 2.77 EC. The icon will disappear
after 30 days to remind you for re-
calibration.
• Water droplets are added
during production to maintain
the moisture of the probe. This
is normal practice and should
not be attributed to used
product.
• The fill line shows the level
to which you should pour
the soaking water or sample
solution.
• For details of probe storage, see
Section 7.
Short Press
Long Press
Premium EC Probe
• Titanium alloy conductivity sensor, highly accur-
ate and requires minimal maintenance
• The probe is replaceable, saving money in the
long run.
01
02
Main Features
page
Main Features
Preparation Before First Use
EC Calibration
EC/500ppm/700ppm Measurement
Other Functions
Probe Cleaning
Probe Storage
Battery Replacement
Probe Replacement
Notes
Troubleshooting Guide
Technical Specs
Accessories
Warranty
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Contents
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02
03
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1. Power on
2. Manual hold
Press again to cancel hold.
In measurement mode,
press to turn on/off the
backlight.
Switch mode:
EC→500ppm→700ppm
Power off
Start
calibration
Switch
between
°F and °C
• White for measurement mode
• Green for calibration mode
• Red for calibration error