Combo Meter
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      FAQ and troubleshooting: Bluelab Combo Meter

      General Questions:

      Bluelab Combo Meter 1-small (1)

      How do I change the nutrient and temperature units?

      1. Press and hold the ‘nutrient/units’ or ‘temp/units’ button until the display starts flashing. Release, then short button press the same button to scroll through the units.
      2. Release when the required unit is displayed.
      3. The display flashes four times after the last button press then returns to a normal display, showing the selected unit.

      How do I change the batteries?

      • Batteries are replaced in the Bluelab Combo Meter when the low battery indicator appears on the screen.
      • Open battery compartment by sliding the back cover down and insert 2x AAA batteries as shown on the battery holder. Slide the cover back on. Note: Alkaline batteries are recommended.
      • Important: Check the batteries at least every 6 months for signs of deterioration, rusting or swelling.

      How often do I have to clean and calibrate my probes?

      When the calibration indicator disappears from the display (every 30 days) remember to:

      1. Clean the pH probe tip with Bluelab pH probe cleaner.

      2. Hydrate / store the sensor. Ensure the cap always contains KCl Storage Solution.

      3. Clean the conductivity probe tip.


        The Bluelab Probe Care Kit pH and Conductivity can help you with all your cleaning and calibration needs.

      There is a salt crust on my pH probe – why?

      • The pH probe and the storage cap contains 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 always has sufficient KCl in the storage cap to remain hydrated.

      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.

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

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

      How do I replace the pH probe?

      1. Attach the probe: Connect the probe to the meter via the BNC fitting.

      2. Loosen the storage cap. Hold cap and twist base one full turn, then gently remove. Not loosening before removal will damage the probe.

      3. Calibrate your probe to your Combo Meter. Read how to calibrate your probe here.
      After calibration, it is now ready to use. Caution: always keep your pH Probe stored hydrated with Bluelab KCl Storage Solution.

      Troubleshooting:

      Trouble

      Reason

      Correction

      Nutrient reading low

      Contaminated conductivity/ temperature probe

      Clean conductivity/ temperature probe

      Solution temperature low/ high

      Wait 5 to 10 minutes for reading to stabilise to a constant value

      Temperature reading inaccurate

      Contaminated pH probe

      Clean pH probe

      Incorrect calibration

      Ensure calibration solutions are accurate. Replace if in doubt. Wait longer for readings to stabilise before calibrating to a constant value

      Calibration unreliable

      Calibrate pH probe

      pH probe damaged or old

      Replace pH probe

      pH reading does not change from solution to solution

      Broken glass bulb, tube or connector

      Check pH probe for damage. Replace pH probe

      Displays low battery indicator *Battery image*

      Insufficient power to take a reliable reading

      Replace the batteries. DO NOT use rechargeable batteries

      No display

      Batteries dead or inserted incorrectly

      Check batteries are inserted correctly. Replace if necessary

      Display shows ‘Err’

      Problem with pH calibration

      See error message descriptions in section 10 of the Bluelab Combo Meter Manual

      Or
      Ur
      While in pH mode

      Over range pH.
      Under range pH

      Solution > 14.0 pH.
      Solution < 0.0 pH.
      Check pH probe connection. pH probe could be faulty. Combo Meter could be wet inside

      Or
      Ur
      While in temp mode

      Over range temperature. Under range temperature

      Solution >51 °C / 122 °F.

      Solution <0 °C / 32 °F.

      Conductivity/temperature probe or Combo Meter faulty.

      Or
      While in conductivity/ nutrient mode

      Over range conductivity/ nutrient

      Over range conductivity >9.9 EC, 99 CF, 4950 ppm 500, 6930 ppm 700. Conductivity/temperature probe or Combo Meter faulty.

      Further resources:      

      Getting started: Bluelab Combo Meter

      How to hydrate your pH probe

      How to clean Bluelab pH Pen and Bluelab pH Probes [+ video]

      FAQ and troubleshooting for Bluelab pH probes