Hach 2100P Instrument And Procedure Manual page 38

SECTION 3,
•
Do not transfer the standard to another container for storage.
•
Do not return standard from the sample cell back into the its
original container. Standard contamination will result.
•
Store standards between 0 and 25 °C.
•
For long-term storage, refrigeration at 5 °c is recommended. Do not
store above 25 °C.
•
Allow the standard to acclimate to ambient instrument conditions
before use (not to exceed 40 °C).
•
Store away from direct sunlight. Store vials in their respective kit or
shipping box with the cover in place.
3.6.1.2 Preparing Bulk StablCal Stabilized Standards
Bulk standards that have been sitting undisturbed for longer than a
month must be shaken to break the condensed suspension into its
original particle size. Start at step 1 for these standards. If the standards
are used on at least a weekly interval, start at step 3.
Important Note: These instructions do not apply to <0.1-NTU* StablCal
Standards; <0.1NTU StablCal Standards should not be shaken or inverted.
1. Shake the standard vigorously for 2-3 minutes to resuspend
any particles.
2. Allow the standard to stand undisturbed for 5 minutes.
3. Gently invert the bottle of StablCal 5 to 7 times.
4. Prepare the sample cell for measurement using traditional
preparation techniques. This usually consists of oiling the sample
cell (seeSection 2.3.2 on page 23) and marking the cell to maintain
the same orientation in the sample cell compartment (see
Section 2.3.3 on page 24). This step will eliminate any optical
variations in the sample cell.
* Used in place of the dilution water standard when performing a calibration.
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