Place the test blank in the spectrophotometer cell holder well(5, fig. 2-5). Put the "Turbidity
(Absorptometric Method)" meter scale card(2) into the spectrophotometer. Adjust the wavelength dial(8) to
450 nm. Turn the LIGHT CONTROL knob( 0) until the meter scale(l4) reads 0.
Remove the blank. Place test sample in spectrophotometer cell holder(5). Read results from meter
Interpretation of Results:
In this test turbidity is measured by finding the amount of light that is blocked out by the turbidity (cloudiness) of
the sample. Results are given in units called FTU. FTU stands for Formazin Turbidity Units. Formazin is a
chemical that causes a milky turbidity when added to water. The meter scale card is marked with FTU units that
correspond to specific concentrations of formazin required to get the amount of turbidity present.
Refer to para 2.6.2 for shut down of the Spectrophotometer.
2.6.9. Decals and Instruction Plates.
2.6.10. Preparation for Movement.
The WQAS-PM is a portable unit and is designed to be transportable without modification or special packing. Ensure
that all components are properly stored in the foam cavities and that the case is securely closed and fastened. If the unit
is to be air transported, open the air valve on the main carrying case.
SECTION IV. OPERATIONS UNDER UNUSUAL CONDITIONS
2.7. UNUSUAL ENVIRONMENT/WEATHER.
2.7.1. General. The WQAS-PM is not designed for optimal performance under extreme environmental conditions. The
best operating temperature for the system is from 68 to 77°F (20 to 25°C). The further from this range the less accurate