It is essential when growing with a hydroponic solution to KNOW what the strength of the solution is before feeding your plants AND while they are growing. This is easy if you use the Bluelab Truncheon! To take a reading of your solution - simply place the probe head into the solution for 1-2 minutes to reach the same temperature of your nutrient. Remove from the solution and place back in to take the reading as indicated by the flashing lights. Rinse the probe after use in fresh water and clean once a week to ensure the Truncheon Nutrient Meter remains accurate.
Calibration of the Meter is not required and it's great for stirring your nutrient tank too!