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GroLine Monitor – Data logging, Graphing, Backlit screen, Alarms With Inline Probe


The HI981421 GroLine Monitor for Hydroponic Nutrients provides around-the-clock, continuous monitoring of pH, conductivity (EC & TDS), and temperature in hydroponic nutrient solutions. Quick to setup, simple to use, this monitor was designed with Hydroponics, Aquaponics, and Greenhouses in mind. Make your nutrient solution easy to manage with the GroLine Monitor.

Get 24/7 pH&EC measurements for consistent yields every time.
Good Laboratory Practice (GLP) feature for professional accuracy.
Calibrate pH and EC with a single Quick Cal solution.

SKU: HI981421 Category: Brand:


Features at-a-glance
3 sensors combined in a single rugged probe body made for continous immersion up to 2 meters: pH electrode with renewable cloth junction, amperometric EC/TDS sensor, and an internal temperature sensor for temperature compensated readings
IP65 rated enclosure: designed to withstand harsh grow environments
Wide pH Range: measure pH from 0.00 to 14.00 pH
Selectable EC to TDS/ppm conversion factor: choice of either a 0.5 or 0.7 conversion factor
Automatic Temperature Compensation: all readings are compensated for variations in temperature, temperature displayed in oC or oF along with pH, EC or TDS reading
Large LCD with plant-friendly green backlighting: LCD can display all three essential hydroponic nutrient measurements at one time, a 3-second cycle of single measurements, or a real-time graph screen with options for measurement selection and log recall
Data logging for 30 days: logs every 15 minutes for last 30 days, stores min, max, and average values
Data transfer: USB-C port for easy data transfer to memory stick or PC
High and low alarms: warns when your nutrient solution is out of desired range by flashing display and message
Ambient light sensor: for automatic LCD dimming. Specification Name Detail
SKU HI981421-01
pH Range 0.00 to 14.00 pH
pH Resolution 0.01 pH
pH Accuracy (@25°C/77°F) ±0.05 pH
Temperature Range 0.0 to 60.0°C / 32.0 to 140.0°F
Temperature Resolution 0.1°C / 0.1°F
Temperature Accuracy (@25°C/77°F) ±0.5°C /±1°F
EC Range 0.00 to 10.00 mS/cm
EC Resolution 0.01 mS/cm
EC Accuracy (@25°C/77°F) ±0.1mS/cm (0.00 to 5.00mS/cm); ±0.2mS/cm (5.00 to 10.00mS/cm)
TDS Range 0 to 5000 ppm (TDS conversion factor 0.5 (500 CF)); 0 to 7000 ppm (TDS conversion factor 0.7 (700 CF))
TDS Resolution 10 ppm
TDS Accuracy (@25°C/77°F) ±2% F.S.
Temperature Compensation pH: automatic (0.0 to 60.0ºC/ 32.0 to 140.0°); EC: automatic with β set at 1.9%/°C
Calibration pH calibration at one or two-point calibration (using pH 4.01,7.01, 10.01 buffers) using auto buffer recognition; one-point calibration using quick calibration solution; EC calibration at one-point at 1.41 mS/cm or 5.00 mS/cm using auto standard recognition; one-point calibration using quick calibration solution
Log Feature Automatic logging for last 30 days at 15 minute interval
Alarms High and Low with enable/disable option for all parameters
Connectivity USB Type-C
GLP Good Laboratory Practice with last 5 pH and EC calibration history
Power Supply 12VDC adapter (included)
Environment -5 to 50°C (23 to 122°F); RH max 95% non-condensing
Dimensions 125 x 185 x 38 mm (4.92 x 7.28 x 1.49”)
Weight 333g ( 11.7oz.)
Ordering Information HI981421 is supplied with HI1285-9 multiparameter probe, Quick Cal buffer solution sachets (2), HI700661 electrode cleaning solution sachets for agriculture (2), 12VDC power adapter, quality certificates and instruction manual.

Additional information

Weight 3 lbs
Dimensions 1 × 3 × 6 in


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