The instrument is only as accurate as the probe is clean probe cleaning is one of the most important parts of owning and operating any Bluelab meter or controller. If the probe is contaminated or dirty, it affects the accuracy of the reading displayed. The probe surface is where the instrument takes the reading of the solution. The information is sent back from the probe to the electronic brain of the instrument. A calculation is then done in the instruments brain or micro computer and a reading is then displayed. If the information sent back from the probe is inaccurate due to probe surface contamination then the reading will be inaccurate. Cleaning the probes is a very easy task and prolongs its life.