Sper Scientific LUTU-2016 Turbidity Meter - Manual (Page 12)

Then the Display will show :
100
CAL ntu
Now the meter is finished the " 0 NTU " calibration
procedures and ready for " 100 NTU " calibration
procedures.
7) 100 NTU calibration
When finish the " 0 NTU " calibration procedures and
the Display show :
100
CAL ntu
The meter is ready for " 100 NTU " calibration.
* Insert the " 100 NTU standard solution into the
" Container " ( 3-2 , Fig. 1) and envelope in the " Cover "
( 3-1, Fig. 1 ) completely.
Press " CAL Button " ( 3-5, Fig. 1 ) once, the
Display will show following text with flashing ( approx.
10 seconds ).
flashing
CAL
100 ntu
10