The Apera GroStar GS4 (AI104G) is a second-generation, lab-grade handheld meter designed to measure five parameters for nutrient solution monitoring: pH, electrical conductivity (EC), TDS using the 500 ppm scale, TDS using the 700 ppm scale, and temperature. Its replaceable combination probe integrates a double-junction pH sensor with a titanium conductivity sensor, providing a practical solution for routine nutrient testing in hydroponic and coco-coir cultivation. The IP67-rated instrument features a three-color backlit LCD, automatic temperature compensation, and TruRead mode, which records stabilized readings and calculates their average, minimum, and maximum. The kit includes calibration and probe-storage solutions, allowing growers to begin testing without purchasing these supplies separately.
• Product Type: 5-in-1 pH/EC/PPM/temperature combo pen tester
• Brand: Apera Instruments
• Model: GroStar GS4 (Gen II)
• SKU: AI104G
• Measurement Parameters: pH, EC, 500 ppm, 700 ppm, and temperature
• pH Sensor: Replaceable double-junction electrode
• EC Sensor: Replaceable titanium conductivity sensor
• Calibration: Automatic two-point pH calibration and single-point EC calibration
• Display: Three-color backlit LCD — white for measurement, green for calibration, and red for calibration errors
• TruRead Mode: Records stabilized readings and automatically displays average, minimum, and maximum values
• Temperature Compensation: Automatic temperature compensation (ATC) for EC measurements
• Waterproof Rating: IP67
• Power Supply: Standard AAA batteries with automatic shutoff
• Probe Replacement: Replaceable probes; compatible with GroStar pH, Soil pH, EC, and pH/EC combination probes
• Liquid Testing: Suitable for nutrient solutions and reservoir monitoring
• Growing Media Compatibility: Suitable for cultivation environments using coco coir and other common growing media; direct soil or media testing requires the compatible GroStar Soil pH probe
• 500 ppm Scale: Uses an NaCl-based EC-to-TDS conversion factor
• 700 ppm Scale: Uses a KCl-based EC-to-TDS conversion factor
• Included Calibration Solutions: pH 4 and pH 7 solutions, 50 mL each
• Included EC Calibration Solution: 2.77 EC solution, 50 mL
• Included Storage Solution: KCl solution, 10 mL
• Other Included Accessories: Lanyard and user manual
• Warranty: 2 years for the instrument and 1 year for the probe