The Irrometer operates on the tensiometer principle and has been the industry leader since 1952. The Irrometer consists of a sealed water-filled tube equipped with a special vacuum gauge and with a porous tip that is installed in the ground at desired root zone depths. When the soil is dry, water is drawn out of the instrument, which is registered on the gauge. When irrigation occurs, the vacuum draws water from the soil back into the instrument. The Irrometer, in effect , is a dummy root.
Low Tension Models are designed to operate in coarse, sandy soils and in non-soil planting mixes.
"Please note that for every new set of Irrometers you will need a Service Unit"