TC-3000 Meter Troubleshooting Guide
Negative Results
The 2020e and 2020i turbidity meters will display negative results if the sample water is less turbid than the blank reading. This is possible in ultra- low turbidity waters, where the sample turbidity is at or near the detection limit of the meter.
Negative readings can also indicate a problem when the meter was blanked. If the meter is accidentally blanked to a 1.0NTU standard, subsequent tests may negative, in response to the high blank reading. Correct this problem as follows:
- Reset the meter to the factory calibration settings: with the meter turned OFF, hold down the *OK button and press ON. Release both buttons at the same time. Press *OK to select the default settings. Press *OK again and the meter will turn off. The factory settings will be restored.