Reading below the
DPD-1 measurement
Reading above the
DPD-1
Manual PRO v.2
the water without free
chlorine
Insufficient flow in the sensor
holders
There are air bubbles in the
measuring zone of the sensor
Sensor passivated for
working at more than 3 mg/l
The pH of the water is higher
than at the time of calibration
The pH is above 9, and
therefore outside the
recommended reading zone,
The sensor has been
calibrated without waiting for
sufficient conditioning time
DP-! Reactives are worn
DPD-1 measurement is
incorrect owing to a sample
of water with high salinity
1 hour.
Adjust the flow reaching the sensor
holders. Clean the filter and the flow
regulator of the sensor holders.
Bleed the sensor holders and ensure
that there is no air remaining in the
measuring zone.
Clean the sensor by submerging it in
an HC10.1M solution for 20 seconds.
Calibrate the sensor to the new pH
value.
Adjust the pH within the acceptable pH
range: 6.5-9
Repeat conditioning of the sensor and
recalibrate.
Repeat the DPD-1 measurement with
new reactives
Increase the waiting time in the
reaction of the DPD measurement
reactives.
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