VOLTCRAFT NTU-600 Mode D'emploi page 25

• Always handle the glass bottle by touching only the cap or its top side (threaded part). Use
the supplied cloth to wipe the bottle surface clean.
• Before a glass bottle is placed into the sample holder of the instrument, it must be dry
outside, completely free of any glass imperfection.
• After a glass bottle is used, rinse it inside and outside with clean water in a thorough way.
Allow it to air dry, then store it in the supplied bottle holder with a cap. This can prevent dirt
and dust entering inside.
Standard solution and calibration
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• The standard solution set includes three glass bottles in which the standard solution is
contained (named 0 NTU, 100 NTU and 800 NTU). The standard solution (2) is exclusively
used in calibration for achieving accurate measurements.
• Before taking a standard solution bottle to perform a calibration, fully mix the standard
solution in the bottle, so that a best measurement can be made.
• Gently hold the bottle upside down (by gripping the bottle cap), then inverse it to the stand-up
position. Repeat this several times to fully mix the standard solution.
• Do not shake the bottle to prevent air bubbles present, because air bubbles can affect the
turbidity readings.
• If there is some material suspended in the standard solution, wait for a few minutes until the
suspended material settles.
• The standard solution has a service life. Use the standard solution before the expiration date
marked on the standard solution bottle.
Sample preparation
4
• It is very important to select a representative sample for constant results.
• Gently mix the water before taking the sample.
• Handle the sample carefully to avoid spillage of the sample into the instrument.
• Analyze the sample immediately after collection because the turbidity can change with time.
To avoid dilution of the sample, rinse the testing glass bottle and measuring cup (3) with an
•
amount of the sample and discard the liquid, then refill the testing bottle with the sample for
measurement.
• Any air bubbles present in the sample can cause high turbidity readings. Remove air
bubbles before taking measurements.
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