Hach-Lange 2100 N Laboratory Turbidimeter User Manual - Manual (Page 23)

7. Repeat step 6 until
the lowest value is
shown on the display. 8. Record the value.
Put an orientation mark
on the marking band
near the top of the
sample cell. 9. Put the second
sample cell in the
sample cell holder.
Close the cover.
Record the value when
stable. 10. Remove the
sample cell, turn it
about
1 /
8
of a turn and
put it in the sample cell
holder again. Close the
cover.
Record the value when
stable.
11. Repeat step
10 until the value
matches the first
sample cell value within
±0.005 NTU. 12. Put an orientation
mark on the marking
band near the top of the
sample cell where the
lowest value is shown.
13. Do steps 9–
12 again as necessary
to match the other
sample cells prepared
in steps 1–4.
Prepare dilution water
Dilution water is used when indexing a sample cell or matching sample
cells and to prepare formazin standards.
1. Collect at least 1000 mL of high-quality, low-turbidity water (i.e.,
distilled, demineralized or deionized water or filtered tap water).
2. Measure the turbidity of the water using the turbidimeter. Refer to
Turbidity measurement on page 24.
3. If the turbidity of the water is greater than 0.5 NTU, filter the water
using the sample filtration and degassing kit. Refer to the user
instructions provided with the sample filtration and degassing kit.
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