LaMotte Dissolved Oxygen Water Quality Test Kit - Manual (Page 18)

18
EPA COMPLIANCE continued ...
Read the test result directly from the scale
where the large ring on the Titrator meets the
Titrator barrel. Include the value of the original
amount dispensed (1 mL). If the reading is 2.0
+/- 0.1 mL, the Sodium Thiosulfate, 0.025N
(4169) is satisfactory. If not, discard and replace
with new reagent
While gently swirling the
tube, add Sodium
Thiosulfate, 0.025N until
the color fades to pale
yellow. It will be
necessary to refi ll the
Direct Reading Titrator.
Add 3 drops of
Starch Indicator
Solution (4170WT).
The solution will
turn blue.
Continue adding
Sodium Thiosulfate,
0.025N until the blue
color disappears and
the solution is colorless.
7. 8.
9.
10.