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Direct Soil and Soilless Media pH electrode for use with HI9814
The HI12943 is a pH electrode for the direct measurement of pH in soil and soilless media. The HI12943 is a glass body, refillable, single junction pH electrode with a DIN connector that is compatible with the HI9814 Groline portable pH/EC/TDS meter. This electrode has a triple ceramic junction in the outer reference cell and the conic pH sensing tip is made with low temperature glass. There is an integrated amplifier and built-in temperature sensor for automatically temperature compensated pH readings. The design consideration for the HI12943 is ideal for pH measurements in soils and hydroponics growing media including rockwool, coconut cour, perlite and other soilless substrates. The HI12943 can only be used with Hanna’s HI9814 Groline portable pH/EC/TDS meter. *HI1293 is replacing HI1294D. Both electrodes are compatible with existing models of HI9814.
Triple Ceramic Junction
Low Temperature Glass
Built-in Temperature Sensor
Low-Temperature Glass Formulation
The glass tip uses a special LT glass formulation with a lower resistance of approximately 50 megaohms compared to general purpose (GP) with a resistance of about 100 megaohms. As the temperature of the glass decreases when in a sample at low temperature, the resistance of the LT glass will increase approaching that of GP glass at ambient temperatures. If using GP glass, the resistance would increase above the optimum resistance for the high impedance input of a pH meter. The HI12943 is suitable to use with samples that measure from -5 to 70C.
The conical shaped tip design allows for penetration into solids, semi-solids, and emulsions. The HI12943 is ideal for the direct measurement of pH in soils and soil slurries.
The glass of the HI12943 is resistant to many harsh chemicals and is easily cleaned. The glass body also allows for a fast transfer of heat to the internal reference electrolyte. The mV generated by the reference cell is temperature dependent. The faster the equilibrium the steadier the reference potential.
Triple Ceramic Junction
The triple ceramic junction allows a higher flow rate of electrolyte from the reference cell into the measurement sample. A typical pH electrode will have a single ceramic junction that flow rate of 15 to 20 µL/hour. The HI12943 has three ceramic junctions in contact with the sample providing for a flow rate of 40 to 50 µL/hour. The increased flow provides a greater continuity between the reference electrode and the indicating electrode.
The HI12943 is a refillable probe. Since it is a single junction pH electrode the fill solution is the HI7071 3.5M KCl + AgCl. If using a refillable pH electrode, the fill cap should be removed prior to calibration and measurement. Removing the cap creates positive head pressure in the reference cell allowing for a higher flow rate of electrolyte through the outer junction. A higher flow rate will result in a faster and more stable reading.
Specification Name Detail
Description pH electrode
Reference single, Ag/AgCl
Junction / Flow Rate ceramic, triple / 40-50 µL/h
Electrolyte KCl 3.5M + AgCl
Max Pressure 0.1 bar
Range pH: 0 to 12
Recommended Operating Temperature -5 to 70°C (23 to 158°F) – LT
Tip / Shape conic (12 x 12 mm)
Temperature Sensor yes
Body Material glass
Cable 7-pole; 1 m (3.3’)
Recommended Use direct soil, soilless media, soil solution
Connection Quick Connect DIN*
Special Note * Only for use with HI9814 GroLine multiparameter meter