Trace2O AquaSafe WSL25 Plus, Instruction Manual

Page: 43 / 85

SECTION 2: ANALYSIS
Good illumination is essential for accurate use of the turbidity tube.
Look through the open end of the tube, at the black square on the base of the tube. This is the Trace2o Secchi
marker.
Hold the tube vertically, and slowly pour the water sample to be analysed into the tube, until the moment that
the Secchi marker is no longer visible from the top of the tube.
Alternatively, fill the tube, then slowly pour small portions away, until the moment that the Secchi marker
becomes visible from the top of the tube.
Hold the tube vertically, and identify the water level.
The turbidity value is that marked next to the graduation line nearest the water level.
The graduations follow a logarithmic scale, with the most critical values marked on the tube, and therefore the
turbidity tube can only ever be an estimate for the turbidity of the water sample.
Note: bubbles may cause false readings.
The turbidity tube is calibrated to a person with normal (6/6) visual acuity.