Hanna Instruments HI 9829 Instruction Manual page 88

The calibration solutions and displayed measurements are as ppm Chloride
ions. Due to the space restriction of the display the unit of measurement will be
displayed as "ppmCl" (without charge).
The chloride sensor will last longer in colder clean waters than in severely
contaminated water or warmer waters. This is because the external surface of
the sensor responsible for the chloride ion sensitivity can react with water
contaminants or be leached out of the sensor with continued exposure. As the
sensor ages there will be a decreased sensitivity until the sensor will no longer
calibrate or operate properly. The lifetime of the sensor depends greatly on
deployment conditions.
Although HI 7609829-11 is selective toward chloride ions, it also responds to
other ions.
The interfering ions sulfide, cyanide, and mercury ions must be absent.
The interfering ion to Cl - ratio must be less than the ratio indicated below:
Iodine: 1.0
Bromide: 3.5
Carbonate: 3.5
Hydroxide: 1.0
Thiosulfate: 0.01
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