Clean, hydrate and calibrate your pH probe monthly
To get the longest life and the most accurate measurements from your pH products, clean, hydrate then calibrate your pen before first use and monthly.
Note: This guide applies to all Bluelab pH Probes.
Clean
- Remove the cap.
- Fill a plastic cup with tap water and add a few drops of cleaner.
- Swirl the pen in the solution and rinse with fresh clean tap water to remove solution.
- For heavier contamination, use a soft, clean toothbrush to gently scrub the probe then rinse with fresh clean tap water.
Read the guide on cleaning Bluelab pH probes (+video)
Hydrate
Keep your probe hydrated with Bluelab KCl solution.
1. Add enough KCl storage solution to submerge the probe tip in a plastic cup and leave to soak for 24 hours.
2. Make sure there are a few drops of KCl solution in the storage cap.
Read the guide on how to hydrate your pH probes
Calibrate
Calibrate after every clean and at least monthly.
- Turn the pH pen on.
- Calibrate to pH 7 by placing probe tip in fresh pH 7 solution. Wait for reading to stabilise to between pH 6.6 - pH 7.5.
Long press the Cal button until CAL is displayed. Release the button. A calibration sequence will start sequentially flashing “0” across the display. After “0000” stops flashing, the sequence is complete. Rinse the probe tip in fresh tap water. - Repeat with pH 4 solution.
- A checkmark will confirm successful calibration.
Read the guide on how to calibrate your pH probe (+ video)
Quick tips for care
Don’t let the probe tip dry out. If it accidentally dries, re-hydrate your probe for 24 hours in KCl storage solution and re-test.
Don’t knock or drop the pen. This may break the external glass bulb or the internal glass tube.
Don’t touch the glass bulb with your fingers. This will contaminate the glass.
Don’t plunge a cold probe into a hot liquid or vice-versa. Sudden temperature changes can crack the glass and permanently damage the pen.
Don’t soak the pen in RO (Reverse Osmosis) water (rinsing in RO water is acceptable, but never soak or rinse in distilled or deionised water.
Don’t immerse in oils, proteins, or suspended solids that will leave a coating on the glass bulb.
pH probe storage best practices
Keep the probe tip moist. Add KCl solution to the well on the inside of the cap once a week. Never use RO, distilled, or deionised water. Place the seal and cap over the probe tip.
For long-term storage (e.g., between growing seasons), remove the cap and place the pen upright in a plastic container. Cover the probe tip with KCI storage solution to ensure constant hydration. Check the container regularly and top up the KCI solution as needed.
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