Replacement Conductivity Cells, K = 0.1, 1 and 10

Worth knowing before you order

The cell constant is the whole decision here and the commonest and most expensive ordering mistake in this part of the catalogue. K = 0.1 is for high-purity and deionised water at the microsiemens end, K = 1 for ordinary drinking and laboratory water, K = 10 for brines and concentrated effluent — and the ranges above barely overlap, so a cell used outside its band still returns a plausible-looking figure that is simply wrong. These are consumables: the platinum foils foul and the effective constant drifts, so recalibrate against a standard solution rather than trusting the nominal K, and replace rather than scrub a cell whose reading will not come back. Check the meter socket before ordering — the cells terminate in a 6-pin mini plug, and some meters in the same range use a 6-pin mini-DIN with a separate 3.5 mm jack.