Ensure accurate readings every time by calibrating your pH pen or probe to 2 points monthly
Calibrating your pH pen or probe will ensure accurate readings. To get the best from your pH product, we recommend calibrating once a month.
Calibrating your pH pen or probe is required:
- Before first use
- If the calibration reminder has disappeared from the LCD screen (30 days after first calibration)
- If the pH measurement is different from what you expected
- After cleaning and hydration
- After changing the batteries
Note: Bluelab pH products should always be calibrated to 2 points using fresh pH 7 and pH 4 solutions. If your readings will be higher than pH 7, you can use pH 7 and pH 10 solutions.
To calibrate your pH pen or probe, follow the steps below.
1. Make sure your pen or probe is clean and hydrated
Follow the Bluelab pH Probe cleaning guide and Bluelab pH Probe hydration guide before calibration.
2. Turn the pH pen or probe on
Press “power/hold” button.
3. Calibrate to pH 7
Place probe tip in fresh Bluelab pH 7.0 Calibration Solution. Wait for reading to stabilise to between pH 6.6 - pH 7.5.
Long press the Cal button on the pen or meter until “CAL” is displayed. Release button. A calibration sequence will start, sequentially flashing "0" across the display. After "0000" stops flashing, the sequence is complete, and “pH7” is displayed. 
4. Rinse
Rinse pen or probe tip well in clean tap water and shake off excess.
5. Calibrate to pH 4
Place probe tip in fresh Bluelab pH 4.0 (or pH 10) calibration solution. Wait for the reading to stabilise between 3.6 pH - 4.5 pH.
Long press the Cal button until “CAL” is displayed. Release button. A calibration sequence will start, sequentially flashing "0" across the display. After "0000" stops flashing, the sequence is complete, and “pH4” (or “pH10”) is displayed.
6. Confirm calibration
A calibration confirmation will be displayed at the bottom of the pen or meter screen to indicate a successful calibration. It will disappear after 30 days to indicate calibration is required.
Having trouble with calibration or is the pH pen showing an error code? Read our troubleshooting and error code guide.
Useful resources
How to hydrate your Bluelab pH Pen
How to clean Bluelab pH pens and probes
How to take a measurement with the Bluelab pH Pen
FAQ and troubleshooting guide for the Bluelab pH pen and probes
Still can’t find what you're looking for? Contact Support