Equitensiometer EQ3

Delta T EQ3 Equitensiometer measures water potential (matric potential) in the range 0 to -1000 kPa. Is an accurate and reliable alternative to water-filled tensiometers, particularly well suited for use in dry soils. Built in temperature sensor. Buriable and frost resistant (IP68). Maintenance free.

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The EQ3 Equitensiometer is ideally suited to static long term monitoring of water potential in soils and substrates. It can be buriable and even be left installed in frozen soils. Low energy consumption make it useful to install at remote sites over long periods of time. In such instances it is possible to access sensor data wirelessly. Typical applications include environmental, plant, soil, ecology and geo-sciences research, as well as civil engineering and agricultural engineering applications.

The EQ3’s full range is 0 to -1000 kPa but best accuracy is achieved between -100 and -500 kPa. This makes it well suited to plant water stress studies – even in very dry soils.

The EQ3s measuring rods are embedded in a porous material. This material has a known, stable relationship between water content and matric potential. When the EQ3 tensiometer is inserted into the soil, the matric potential within the sensor equilibrates to that of the surrounding soils. The water content of the matric material is measured and it can be converted into the matric potential of the surrounding soil using the calibration curve supplied with each Equitensiometer.

Despite its many strengths, the EQ3 should not be seen as a rapid response sensor that covers the full range of water potentials at high accuracy. Such a sensor does not yet exist. EQ3 equilibration time is typically several hours.

The EQ3 can also be used with an HH2 Moisture Meter, but only the unconverted millivolt output is displayed, and the temperature reading is not available.


Soil water potential (matric potential) and soil temperature


± 10 kPa over 0 to -100 kPa

10% of reading over -100 to -1000 kPa

± 0.5°C (0 to 40°C for temp sensor)

± 0.75°C (-20 to +60°C for temp sensor)

Soil moisture measurement range

0 to -1000 kPa (-10bar)

Salinity range

Suitable for all non-saline soils

Power supply

5 – 14 VDC

Power consumption

~18 mA for 1s

Operating temperature

0 to + 40 ° C

Sample volume



181 mm, 40.5 mm diameter


0.3 kg (excl. cable)

Sensor calibrations

Individual sensors calibrations supplied. Recalibration advised every 2 years (depending on use)

Soil calibrations

No soil calibrations required



Output signal

0 to 1.0 V differential, non-linear

(Calibration data and graph supplied with each sensor)

Resistance 5.8Ω to 28Ω for temp sensor


Moisture meter HH2


User manual EQ3  EQ3_User_Manual_v1_1.pdf 

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Equitensiometer EQ3
Equitensiometer EQ3
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