Operation and maintenance of pH meters
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Learn how to handle and maintain your pH meter and pH electrode from Metrohm.
On this page, you can find information on how to calibrate your pH meter or pH electrode and which maintenance intervals you should take into account.
How to handle your pH meter and electrode
Follow these general handling instructions to ensure reliable pH measurements:
- Use fresh pH buffers and check their expiry dates.
- Rinse pH electrodes with deionized water before and after each measurement.
- Store pH electrodes in the appropriate storage solution and follow the recommendation in the leaflet to prolong their lifetime.
- Always place the glass membrane and reference system in the storage solution when not in use.
- Remove deposits with suitable cleaning solutions (e.g., acid or alkaline cleaners depending on contamination).
- Perform calibrations at least weekly or before critical measurements. Use two or more buffer solutions for calibration.
Calibrating a pH electrode
Over time, every pH electrode ages, which leads to changes in the slope and offset potential. This is why calibrating your pH electrode regularly is important.
This video shows:
- calibration intervals
- the equipment you need to perform a calibration
- how to perform the calibration
General instrument maintenance
By following recommended maintenance routines, you ensure the integrity of your results and optimize performance for critical applications.
- Once per week (or when necessary): wipe the display and keypad with a soft, damp cloth and a mild detergent. Ethanol or isopropanol may also be used. Avoid acetone or other aggressive solvents.
- Every six months: inspect cables and connectors for damage.
- At least once per year: check for available firmware updates to ensure continued safe and reliable operation. Security‑relevant firmware updates are provided throughout the product’s support period.
- Once per year: perform operational qualification by a trained service person to verify the correct measuring signals for pH, conductivity, and temperature.
Troubleshooting
The following are a few general tips to troubleshoot your pH meter:
- Unstable pH readings: check for air bubbles on the pH electrode, clean the pH electrode with a pHitKit, and recalibrate.
- Unstable pH readings: check the filling level of your reference electrolyte.
- Slow response time: replace storage solution and clean pH electrode. If unresolved, consider pH electrode replacement.
- Calibration fails: ensure fresh buffers, correct temperature, and proper electrode immersion depth.
- Instrument error messages: restart device, check cable connections, and update firmware if needed.