What are single and double junction pH probes?
A. The reference cell of a single junction probe has a wick or frit that makes direct contact with the solution being measured. They are easy and fairly cheap to manufacture but contamination occurs faster in a single junction probe and generally last 6 months. The reference cell of a double junction probe has a wick or frit that makes contact with a second chamber filled with the same material as in the reference cell. This second chamber has a wick or frit that makes direct contact with the solution being measured. Because it has a second chamber, contamination is slowed. The Bluelab Contact Ring acts as a barrier to the second chamber and is easily cleaned or replaced at a very low cost. The Contact Ring stops contamination getting into the reference cell inside the probe..hence extending it’s life. The Bluelab Contact Ring looks like a ‘Life Saver’ candy so can be thought of as a ‘Probe Saver’. Bluelab Contact Rings are replaced on the Bluelab pH Truncheon every six months but this
