Question
What does a flashing square or zero in the bottom left corner of the display on the DR300 or Pocket Colorimeter II™ mean?
Summary
DR300 or Pocket Colorimeter II™ flashing a small square or zero
Answer
This happens after the batteries have been removed and replaced. The flashing square indicates that the instrument needs to be zeroed before it can take a measurement. Place a sample cell containing the blank solution into the instrument and press the zero key.