A. The instrument is only as accurate as the probes are clean!
This is the most important piece of maintenance required on any Bluelab instrument. The probes are what come into contact with the solution and relay the reading back to the instrument for it to be displayed. The probes are susceptible to being contaminated or being covered in a greasy film that inhibits an exact reading. There are no shortcuts to cleaning the probes. It is already a very simple procedure and it will also ensure your instrument measures it right every time.
For more information see Bluelab Cleaning Kits or
See how to clean the pH probe correctly
See how to clean the conductivity probe correctly