4. Select Check Standards Options and update the settings:
Option
Standard
Description
Sets the temperature compensated buffer value for check standard—
• 4.01 pH—25 °C
• 4.65 pH—25 °C
• 6.86 pH—25 °C
• 7.00 pH—25 °C
• 9.18 pH—25 °C
• 9.23 pH—25 °C
• 10.01 pH—25 °C
• 12.45 pH—25 °C
• Custom
Standard
Value
The standard value shows on the Check Standard Options screen.
No temperature compensation for custom buffers.
When the Standard is set to Custom, enter the standard value with the up/down arrow keys.
5. Select Check Standard Reminder and update the settings:
Option Description
Reminder Repeat Sets the time interval for the check standard reminder—Off, 30 minutes,
2 h, 4 h, 8 h, 12 h or 24 h.
Allow Defer
Lets the postponement of check standard reminders—Yes or No.
6. Select Acceptance Criteria and update the settings:
Option
Acceptance Limits
Description
Sets the tolerance limits for check standard—0.005 pH (default) to
1.000 pH.
Cal Expires on Failure Recalibration is necessary if check standard fails—Yes or No.
7. If prompted, enter a name for the new method settings. Other changes made to the settings of an existing method are automatically saved with the same method name.
8. Push EXIT until the meter goes back to the measurement mode.
Maintenance
Clean the probe
Clean the probe when there is contamination on the sensor. Symptoms of contamination are:
• Readings are not accurate or consistent.
• The stabilization time is slow.
• A calibration error occurs.
• Contamination is visible on the probe (e.g., dirt).
1. Rinse the probe with deionized water. Blot dry with a no-lint cloth.
2. Soak the glass bulb of the probe in the applicable cleaning agent. Refer to
Table 3 .
Note: Remove KCl salt build-up from the probe with warm deionized water.
3. Rinse or soak the probe for 1 minute in deionized water.
4. Soak the probe in pH 4 buffer for 20 minutes.
5. Rinse the probe with deionized water.
6. Blot dry with a no-lint cloth.
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Contaminant
General contaminants
Mineral deposits
Fats, grease and oils
Protein deposits
Inorganic buildup
Table 3 Cleaning agent
Cleaning agent
Electrode cleaning solution
0.1 N HCl solution
Warm, mild detergent solution
Pepsin cleaning solution
EDTA solution
Soak time
12–16 hours
10–15 minutes
2 hours (maximum)
3 hours (maximum)
3 hours (maximum)
Replace the filling solution
Replace the filling solution and KCl crystals (if applicable) when either occurs:
• The filling solution becomes contaminated.
• The KCl crystals in a Red Rod probe no longer move freely through the liquid when the probe is inverted.
1. Use a syringe or small pipette to remove as much filling solution from the probe as possible.
2. For Red Rod probes, if KCl crystals are still in the probe:
a. Fill the probe half full with the filling solution.
b. With a finger over the filling hole, shake the probe until the crystals become loose.
c. If the crystals will not loosen, fill the probe with filling solution. Put the probe into a warm water bath for approximately 10 minutes (up to 60 °C (140 °F)).
d. Do step 1 again.
3. For Red Rod probes, add approximately 0.5 cm (0.2 in.) of KCl crystals to the probe through the filling hole. For measurements at temperatures more than 60 °C (140 °F), more crystals are necessary. Refer to
Preparation for use
on page 2.
4. Fill the probe. Refer to Fill the probe on page 11.
Fill the probe
Add filling solution to the probe when the filling solution level is low (refer to Preparation for use
on page 2) or is replaced (refer to Replace the filling solution on page 11). Refer
to Specifications on page 1 for the applicable filling solution.
1. If the filling hole is closed, remove the filling-hole cap from the filling hole (refer to
Product overview on page 2).
2. Remove the cap from the tip of the filling solution bottle.
3. Hold the bottle so that the tip is down. Put the tip of the bottle in the filling hole.
4. Slowly squeeze the bottle and fully fill the probe.
Note: Fully fill the probe for the best performance.
5. Put the probe into storage if not used immediately (refer to
Storage
on page 11).
6. Keep the filling solution bottle and cap for later use.
Note: If the dispensing tip becomes clogged, remove the dispensing tip and soak the tip in warm water. Fully dry and assemble the tip.
Storage
Short-term and long-term storage
For the best probe performance, do not let the reference junction become dry.
Note: Keep the probe in a sample for a maximum of 2 hours if the sample pH is not too high.
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