To make a measurement

  1. Drip solution onto prism at centre of stainless steel stage until prism is covered.
  2. Press START/OFF button.
  3. Read measurement.
  4. Mop up test solution with tissue, wipe prism with clear damp tissue, dry.
  5. Either wait 5 minutes for display to switch off or hold down START/OFF button until display switches off or take another measurement.


  1. Perform this once a day or if temperature changes greatly.
  2. Drip distilled/demineralised water onto prism.
  3. Press ZERO button.
  4. Display should read 0.


  1. Measurement is in volume 10-2 Brix %, (sugar solution concentration).
  2. Range 5C<T<40C, 0-45%, accuracy 0.2%, minimum value 0.1%.
  3. Result is temperature corrected to T=20C for sugar solution (irrelevant at laboratory temperatures).
  4. Calibration graph for salt solution below.

  1. Scratch prism surface with metal etc.
  2. Drop it.
  3. Use in direct sunlight.
  4. Leave it damp.
  5. Put battery in the wrong way round or overtighten battery cover.