My pH Pen will not calibrate!

Bluelab pH Pen not calibrating to pH7 or pH4 solution? Hopefully this will help! 

Generally speaking, most of the time, pH pen or pH probe issues are due to cleaning or hydration of the probe, so this is always the first check.

  • If this is your first use with your pH pen, ensure the pH pen has been hydrated in the Bluelab pH Probe KCl Storage Solution provided with the unit for 24 hours (or overnight if the pen needs to be used urgently).
  • If you have already used your pH pen successfully before, but the calibration process now results in an error (Er) message, then further cleaning and re-hydration may be required. Clean your pH pen as per the instructions (soft toothbrush, pH cleaning solution), rinse it well under fresh tap water, and then leave the pen to re-hydrate overnight or for 24 hours in Bluelab pH Probe KCl Storage Solution (other brands of potassium chloride solution may be acceptable, though we recommend Bluelab solution to avoid any complications). 
  • Further cleaning instructions can be found here.
  • Also, check out our Cleaning and Calibration video now available here. 

The pH Probe on your pen is not replaceable! So, this means the pH probe that is attached to your current pH pen needs to be taken care of and maintained as best as possible.

Ensure the probe is well conditioned and stored correctly.

Try to ensure monthly cleaning and re-hydration.

If you follow these steps, this should help ensure a long and happy relationship between you and your Bluelab pH Pen!