LaMotte SMART3 Colorimeter - Manual (Page 288)

PROCEDURE
1. Press and hold until colorimeter turns on.
2. Press ENTER to select TESTING MENU.
3. Select ALL TESTS (or another sequence containing 098 Turbidity) from
TESTING MENU.
4. Scroll to and select 098 Turbidity from menu.
5. Rinse a clean tube (0290) with deionized water (turbidity free). Fill to the 10 mL
line with deionized water.
6. Insert tube into chamber, close lid and select SCAN BLANK.
7. Rinse a second clean tube (0290) with sample water. Fill to the 10 mL line with
sample. Cap tube. Wipe off excess water and fi ngerprints. Shake to resuspend
particulate matter. Remove all bubbles before measurement.
8. Insert tube into chamber, close lid and select SCAN SAMPLE. Record result.
Turbidity measurements should be taken as soon as possible after sample has
been collected.
9. Press to turn colorimeter off or press
EXIT
to exit to a previous menu or
make another menu selection.
NOTE: For the most accurate results, the sample should be at 25±4°C.
PREPARING FORMAZIN SOLUTIONS
The turbidity calibration was prepared by using standard formazin solutions as a
reference. These solutions can be prepared by carefully following the procedure
below.†
1. Dissolve 1.000 g of Hydrazine Sulfate in deionized water and dilute to mark in
100 mL volumetric fl ask.
2. Dissolve 10.00 g of Hexamethylenetetramine in deionized water and dilute to
mark in 100 mL volumetric fl ask.
3. Mix 5 mL of each solution in a 100 mL volumetric fl ask and allow to set
undisturbed for 24 hours.
4. At the end of the waiting period, dilute to mark with deionized water and mix.
5. The turbidity of the stock solution is 400 FTU. The stock solution is stable for
one month. Dilutions from the stock should be prepared fresh daily.
†Alternatively, a prepared concentrated formazin standard of 4000 NTU may be
ordered in a 60 mL size by Code 6195-H.
TURBIDITY SMART3 Test Procedures 11.10
Test P
rocedures