HI GroLine Monitor for Hydroponic Nutrients with Inline Probe

SKU: HI981421-01

505.00 505.0 USD 505.00


The GroLine Monitor for Hydroponic Nutrients provides around-the-clock, continuous monitoring of pH, conductivity (EC & TDS), and temperature in hydroponic nutrient solutions. 

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    HI GroLine Monitor for Hydroponic Nutrients 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 set up, and 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. Inline
    • Calibrate pH and EC with a single Quick Cal solution.
    • A large clear LCD displays all of your essential readings so you know what your hydroponic nutrient solution is doing 24/7. High and low alarms flash warning you if something needs adjusting.

    Groline Monitor Display

    • The GroLine Monitor automatically logs your results every 15 minutes over the last 30 days. Minimum, maximum, and average values are stored so you can recognize when patterns arise and help prevent future problems.
    • Our 3-in-1 pre-amplified inline probe measures pH, EC/TDS, and temperature in a single, durable, polypropylene body making the GroLine Monitor easy to handle and easy to set up. The HI1285-9 has a 3/4” threaded connection for insertion into a pipe for flow-through monitoring.
    • HI1285-9 Inline pH/EC/TDS Multiparameter Probe
    • A single calibration solution for pH and conductivity makes calibration fast and ensures all of your measurements are accurate all of the time for better plant health and better yield.
    • quick-calibration-groline
    • Advanced algorithms and greater pH and TDS/ppm accuracy ensure operational consistency and a finer understanding of your plant’s nutritional needs.
    • Our GroLine Monitor is made by growers and scientists alike who are committed to helping you take your growing operation to the next level.


    • 3 sensors combined in a single rugged probe body made for continuous 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, the 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 the last 30 days, stores min, max, and average values
    • Data transfer: USB-C port for easy data transfer to a 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

    Weight (lbs)0.75
    Length (in)4.92
    Width (in)7.28
    Height (in)1.49
    pH Range0.00 to 14.00 pH; 0.0 to 14.0 pH
    pH Resolution0.01 pH; 0.1 pH
    pH Accuracy±0.05 pH; ± 0.1 pH
    pH Calibrationone or two-point calibration (using pH 4.01,7.01, 10.01 buffers) using auto buffer recognition; one-point calibration using quick calibration solution
    pH Temperature Compensationautomatic (0.0 to 60.0ºC/ 32.0 to 140.0°)
    EC Range0.00 to 10.00 mS/cm
    EC Resolution0.01 mS/cm
    EC Accuracy±0.1mS/cm (0.00 to 5.00mS/cm); ±0.2mS/cm (5.00 to 10.00mS/cm)
    EC Calibrationone-point at 1.41 mS/cm or 5.00 mS/cm using auto standard recognition; one-point calibration using quick calibration solution
    TDS Range0 to 5000 ppm (TDS conversion factor 0.5 (500 CF)); 0 to 7000 ppm (TDS conversion factor 0.7 (700 CF))
    TDS Resolution10 ppm
    TDS Accuracy±2% f.s.
    EC/TDS Temperature Compensationautomatic
    Temperature Correction Coefficientβ set at 1.9%/°C
    EC to TDS Conversion FactorTDS conversion factor 0.5 (500 CF); TDS conversion factor 0.7 (700 CF)
    Temperature Range0.0 to 60.0°C / 32.0 to 140.0°F
    Temperature Resolution0.1°C / 0.1°F
    Temperature Accuracy±0.5°C /±1°F
    Alarm Relay Set Pointhigh and low with enable/disable option for all parameters
    Multi-parameter ProbeHI981421 is supplied with a HI1285-9 probe that has a 3/4" threaded connection for in-line pipe mounting
    Logging Typeautomatic logging for the last 30 days at 15-minute interval
    ConnectivityUSB Type-C for flash drive or compatible device
    GLPlast 5 pH and EC calibrations
    Display128 x 64 pixel B/W LCD with green backlight
    Power Supply12VDC adapter (included)
    Environment-5 to 50°C (23 to 122°F); RH max 95% non-condensing
    IP RatingIP65