Metex 8760CLP Total Free Chlorine & pH Analyzer - Manual (Page 33)

AQUAMETRIX INC.
1-800-742-1413 www.aquametrix.com
33
pH SENSOR INSTRUCTIONS
Preparation for Use
1. Moisten the pH sensor body with tap water and carefully remove the tape and orange plastic storage
cap. Caution should be used in removing this cap; pull straight down. Do not bend the body of the
pH sensor. This can result in damage to the internal element.
NOTE: Save the lower cap for later use in storage of the pH sensor.
2. Rinse away any deposits on the exposed pH bulb and junction area with tap water.
3. For first time use, or after long term storage, immerse the pH electrode in 4 pH buffer for 30 minutes.
This hydrates the pH bulb and prepares the reference junction for contact with test solutions.
4. If air bubbles are visible inside the pH bulb, shake the electrode downward to fill the bulb with
solution.
5. AquaMetrix electrodes are shipped in a pH electrode storage solution buffered to approximately 7
pH. These electrodes are often ready for use immediately with typical accuracy of ± 0.2 pH without
buffering; however, it is strongly recommended that buffered calibration be performed.
6. The pH sensor is ready to be placed in service.
Inserting pH Sensor into Flow Fitting
Insertion sensors should be examined for good clean sealing surfaces and installed carefully. Clean
seals such as O-rings should be lubricated with silicone grease to ensure liquid tight performance.
Remove the storage cap then carefully push the sensor into the insertion fitting until it is seated against
the stop. Tighten the retainer nut to hold the sensor firmly in place. Let the vessel fill with liquid. The
pH sensor should now read the liquid pH.
Removing pH Sensor from Flow Fitting
Simply turn off the sample flow and allow the pressure to drop to zero, then undo the retaining nut and
carefully remove the pH sensor from the flow cell.
Electrode Maintenance
The pH sensor needs to be calibrated periodically to maintain accurate measurements. AquaMetrix
recommends that the electrode be calibrated every 30 days. Depending on the process, it may need to be
calibrated more frequently, eg. weekly or even daily. Frequent calibration is especially important if
accurate measurements are required.
Over time, electrode performance will degrade. The glass bulb becomes less responsive to pH and the
reference electrode becomes depleted. The electrodes will need to be replaced after several years of use
or, depending on the harshness of the process, after several months.
Sensor Storage
Short Term: Rinse the pH sensor in demineralized water then store in a plastic shipping cap of 4.0 pH
buffer solution.
Long term: Clean the pH sensor in electrode wash solution, AM-A1100091, rinse in demineralized
water, then store in a plastic shipping cap of pH electrode storage solution, AM-A1100090.