Myron L TH1 - Manual (Page 19)

15
B. Calibration Tracking Records
To minimize your calibration effort, keep records. If adjustments you
are making are minimal for your application, you can check less often.
Changes in conductivity calibration should be recorded in percent.
Changes in pH calibration (TPH1 & TH1) are best recorded in pH units.
Calibration is purposely limited in the TechPro II to ±10% for the
conductivity cell, as any change beyond that indicates damage, not drift.
Likewise, calibration changes are limited to ±1 pH unit (TPH1 & TH1),
as any change beyond that indicates the end of the sensor’s lifetime and
replacement is recommended.
C. Conductivity, RES, TDS Practices to Maintain Calibration
1. Clean oily films or organic material from the cell electrodes with
foaming cleaner or mild acid. Do not scrub inside the cell.
2. Calibrate with solutions close to the measurements you make.
Readings are compensated for temperature based on the
type of solution. If you choose to measure tap water with a KCl
compensation, which is often done (ref. Temperature Compensation,
pg. 25), and you calibrate with 442 solution because it is handy,
the further away from 25°C you are, the more error you have.
Your records of calibration changes will reflect temperature
changes more than the instrument’s accuracy.
3. Rinse out the cell with pure water after taking measurements.
Allowing slow dissolving crystals to form in the cell contaminates
future samples.
4. For maximum accuracy, keep the pH sensor cap on tight so
that no fluid washes into the conductivity cell.
D. pH Practices to Maintain Calibration (TPH1 & TH1)
1. Keep the sensor wet with Myron L pH Sensor Storage Solution.
2. Rinse away caustic solutions immediately after use.
IX. MEMORy
This feature allows up to 20 readings with their temperatures to be stored
simultaneously for later recall.