Bluelab Meters and Monitors

Understanding the nutrient solution is an important part of successful growing. Growth Technology’s accurate range of Bluelab meters and testing equipment make this task quick and easy.

Bluelab Truncheon® Nutrient Meter

The world’s favourite conductivity meter. Simply brilliant, brilliantly simple!

It is essential when growing with a hydroponic solution to know what the strength of the solution is BEFORE feeding plants and DURING growing.

This is easy with the Bluelab Truncheon® Nutrient Meter!

To take a reading of the solution – simply place the probe head into the solution for 1-2 minutes to reach the same temperature of the nutrient. The reading is indicated by the flashing lights. Calibration of the meter is not required.

Meter length: 40.7cm or 16 1/32 in



  • Fully waterproof
  • Auto on/off function
  • No calibration required
  • Daylight readable blue LED’s
  • Battery operated
  • No buttons, switches or knobs
  • Provided with EC, CF, ppm 700 and ppm 500 scales

  bluelab 5 year..

  • Clean the probe face at least weekly, or even more often if using additives or nutrient solutions that contain oils, as these can contaminate the probe and give an inaccurate reading.
  • On occasion check the accuracy status of the Truncheon, using the Growth Technology EC 2.76 conductivity standard. The Bluelab Truncheon does not require calibration, as this is locked in during manufacture, but checking the status indicates the probe face is being cleaned adequately. Always use fresh solution.
  • Always replace the shroud on the probe to protect the probe face and ensure accurate readings.
  • Wait 5 – 10 minutes for the reading to stabilize if the probe temperature is very different to the solution temperature, and stir the probe in solution or place probe where there is good movement.
  • Check batteries on occasion to check for deterioration or swelling.


  • Don’t touch the probe face with fingers or it will contaminate the probe surface. The only time touching the probe is acceptable is when cleaning the probe with the liquid scourer.
  • Don’t wipe the probe face with a cloth or any object – only shake dry.
  • Don’t use rechargeable batteries.
  • Don’t throw away the Instruction Manual – keep it in a safe place to refer back to, if needed. The cleaning instructions are in the manual and should always be referred to until the grower is confident that the procedure is being carrying out correctly.

My Truncheon turns off before reading is taken

Take out of solution for 3-5 seconds. Dip in solution again and take reading.

The Truncheon is not lighting up when dipped in solution

Clean the probe (follow instruction on page 2 of product manual). If this is unsuccessful, replace batteries.


Truncheon continues to give low readings

Clean probe (important to follow instruction manual).

Ensure unscented cleaner is used.

Plant Lifecycle

Early Grow Grow Bloom

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