Hanna Instruments GroLine pH Electrode

The design is ideal for pH measurements in soils and hydroponics growing media including rockwool, coconut coir, perlite and other soilless substrates. The HI-1294D can only be used with Hanna's HI-9814 Groline portable pH/EC/TDS meter.
Key features at a glance:
Triple Ceramic Junction
Low Temperature Glass
Built-in Temperature Sensor
Refillable with 3.5M KCl + AgCl
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 HI-1294D is suitable to use with samples that measure from -5 to 70°C.
Conic Bulb:
The conical shaped tip design allows for penetration into solids, semi solids, and emulsions. The HI-1294D is ideal for the direct measurement of pH in soils and soil slurries.
Glass Body:
The glass of the HI-1294D is resistant to many harsh chemicals and easily cleaned. The glass body also allow for a fast transfer of heat to the internal reference electrolyte. The mV generated by the reference cell is temperature dependent.
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 with a flow rate of 15 to 20 µL/hour. The HI-1294D has three ceramic junctions in contact with the sample providing a flow rate of 40 to 50 µL/hour. The increased flow provides a greater continuity between the reference electrode and the indicating electrode.
Refillable:
The HI-1294D is a refillable probe. Since it is a single junction pH electrode the fill solution is the HI-7071 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 higher flow rate of electrolyte through the outer junction. A higher flow rate will result in a faster and more stable reading.
DIN Connector:
The HI-1294D has a DIN connector that can only be used with the HI-9814 GroLine portable pH/EC/TDS meter.