How to take a measurement with the Bluelab pH Pen

Before you use the Bluelab pH Pen, you need to hydrate the probe tip in KCl storage solution for 24 hours, then calibrate the pen to 2 pH points. 

1. Turn the pH pen on 

Press the power button. To turn pen off, press and hold the power button until “OFF” is displayed.  

Note: The pen will automatically turn off after 4 minutes to conserve battery power.  

2. Measure pH  

Remove the storage cap, place probe in solution and wait for the reading to stabilise.

Taking a reading with the Bluelab pH pen

3. To hold the reading 

To hold the reading on the display, short press the power button. To turn hold mode off, press the power button again.  

4: Measure temperature

If you prefer to take your readings in °C or °F you can change the temperature units. Hold down the Units button for 3 seconds until the temperature units start flashing. Short press the units button again to cycle between °C and °F. To exit this mode don’t press anything for 3 seconds.  

Note: You can change units while in hold mode by holding down the Units button. 

5: Rinse and replace storage cap solution 

To ensure accurate pH readings, always rinse the probe in fresh water before replacing the cap. Add 3-5 drops of Bluelab KCl Storage Solution into the wetting seal of the cap each week. Make sure the cap is on correctly; it will click when in place. 

Important: Keep your probe tip wet at all times to avoid permanent damage. 

If your readings aren't what you expect, or the pH pen won't take a reading, follow our troubleshooting and FAQ guide


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