Hydra Probe II Soil Moisture Probe with SDI12

  • Multiparameter Sensor Combines soil moisture, soil temperature and electrical conductivity
  • SDI12 interface Connects easily to Adcon telemetry systems
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The Hydra Probe II soil moisture probe is unlike other soil moisture sensors and measures moisture by concurrently measuring both factors which influence this parameter: the conductivity and the dielectric constant. The conductivity is strongly reliant on soil salinity while the dielectric constant is most indicative of water content.

The high frequency electrical measurements which indicate the capacitive and conductive properties of soil are then directly link to the soils moisture and salinity content while a thermistor determines soil temperature. The three parameters are delivered via an SDI-12 interface.

The HydraProbe has a small, precisely defined sensing area which allows accurate measurements in regions where there are strong soil moisture gradients, such as near the soil surface. The probes response time is immediate to changing soil moisture conditions. No calibration of the probe is required. The Hydra Probe is equipped with a direct burial connecting cable which allows for data collection over a large study area in a variety of soil conditions.

Manufactured by: Adcon Telemetry
Model: Hydra Probe II Soil Moisture Probe with SDI12

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Soil moisture, temperature and salinity measurement


Dielectric Constant
Range 1 to 65, where 1= air, 78 = distilled water
Accuracy ± 1.5% or ± 0.2
whichever is typically greater
Soil Moisture
Range From completely dry to fully saturated
Accuracy ± 0.03 water fraction by volume in
typical soil
Range 0 - 20 dS/m
Accuracy ± 2% or ±0.002 dS/m, whichever is
typically greater
Range -10°C to +65°C / 14°F to 149°F
Accuracy ± 0.6°C
Sensing Volume(cylindrical)
Diameter 3.0 cm (1.2”)
Length 5.7 cm (2.2”)
Operating Temperature In soils: freezing to +65°C / 149°F
Protection Tolerates continuous full immersion
Length 12.4cm (4.9”)
Diameter 4.2cm (1.6”)
Weight 200 gr. (probe only)
Output Signal SDI-12
Power Requirements 6-30VDC, typically 20mA

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