FAQ and troubleshooting for the Bluelab pH Pens and pH Probes

Find answers and solutions to common questions for the Soil pH Pen, pH Pen, and Bluelab pH probes

In this guide: 

 

General questions 

My pH product wont calibrate, what should I do? 

The first step is to make sure the glass tip of the probe is both well hydrated and clean.  

If, after both hydrating and cleaning, your pH pen still won’t calibrate, it may be at the end of its life. Please reach out to our support team if you have further questions.  

My pH reading is stuck on 7 pH, what should I do? 

Inspect the glassware for damage. If the pen reading is stuck on 7 pH (or close to that), it is likely the glassware is damaged. The pH pen likely needs replacing. 

My pH probe has accidentally dried out, what should I do? 

The probe must be rehydrated for 24 hours in KCI storage solution (never use RO, distilled or deionised water). Next, carry out a calibration to check the probe hasn’t suffered permanent damage. 

There is a salt crust on my probe – why? 

Both the pH pen/probe and the storage cap contain KCl (Potassium Chloride) solution. The result of a small level of evaporation of KCl is the formation of a salt crust as KCl is a type of salt.

This salt crust is normal and will not harm the probe or meter. Gently wash the salt off under fresh running water. It is essential to ensure that your probe has sufficient KCl in the storage cap at all times to remain hydrated.

How long will my Bluelab pH Pen or Probe last?  

Bluelab's pH products are charged with reference material which expends over time and use. The average life span of a pH pen is approximately 18 months. Good care will help to maintain your pen. Follow our guides to proper hydration, regular cleaning and calibration

The pH pen has a 1-year warranty so if you encounter any issues with your current unit, please feel free to reach out to us for support

What is KCl  Storage Solution? 

Our Bluelab pH Probe KCl (Potassium Chloride) Storage Solution is a storage solution designed specifically for use with Bluelab pH Pens or pH Probes.

Storage solution is used to ensure a pH probe is kept in ideal conditions during storage, while the probe is not in use. Read more about KCl solution


 

Understanding error messages

 

Error code Reason Correction

Temperature under range

Temperature over range 

Calibration solutions may be contaminated   Always use fresh calibration solutions
Probe not hydrated or clean Follow the cleaning and calibration steps  
Probe damaged Replace the pH pen

pH under range 

pH over range 

Wrong calibration sequence Calibrate to pH 7 first, then to pH 4
Probe damaged Replace the pH pen

pH calibration failed

Calibration solutions may be contaminated   Always use fresh calibration solutions
Probe not hydrated or clean Follow the cleaning and calibration steps  
Probe damaged.   Replace the pH pen

Hardware error  

The pH probe may be damaged Check for broken glass on the tip of the pen’s pH probe. Consider replacing your pH pen.  

 


 

Troubleshooting 

 

Trouble Reason Correction
Drift – readings slowly varying  Glassware not clean Clean glassware, hydrate, then calibrate
Wick contaminated or blocked Soak probe in KCl storage solution for 24 hours and retest. Don't measure proteins or oils with the pH pen. You may need to replace the pH pen.
Glassware aged  Replace the pH pen
Unsuccessful calibration  Glassware not clean  Clean glassware
Glassware aged (glassware won't clean) Replace the pH pen
Probe not hydrated Soak the probe in KCl solution for 24 hours and retest
Noisy – readings jumping around Contact zone not immersed correctly Lower pen into solution at least 2cm/1"
Reading stuck on 7 pH Broken glassware Replace the pH pen
Incorrect sample reading following successful calibration
Wick blocked 
Soak probe in KCl storage solution for 24 hours and retest. Don't measure proteins or oils with the pH pen. 

 

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