15
Match sample vials
For the best accuracy and repeatability of turbidity measurement, using one indexed vial is best choice. If you need to use a few vials, match these vials are
necessary.
2.1
Repeat the steps above for each vial and record the measured values.
2.2
Find the closest position of these vials measuring value and mark it.
Addendum 2. Preparation of Standard Formazin Solutions
Preparation of turbidity-free water
Turbidity-free water is used for preparation of turbidity standards and is prepared by filtering deionized water through a 0.45µm or smaller pore-sized
membrane.
Preparation of turbidity standards
•
4000 NTU:
(1)
Dissolve 1 gram hydrazine sulfate [(NH
2
)
2
•
H
2
SO
4
] in filtered water and dilute to 100ml in a volumetric flask.
(2)
Dissolve 10 grams hexamethylenetetramine [(CH
2
)
6
N
4
] in filtered water and dilute to 100ml in a volumetric flask.
(3)
Mix 5.0ml of hydrazine sulfate and 5.0ml of hexamethylenetetramine solutions in a 100ml volumetric flask and let stand 24 hours at 25(±3°C).
•
1000 NTU: mix 25ml of 4000 NTU standard in a 100ml flask, dilute to the mark.
•
500 NTU: mix 12.5ml of 4000 NTU standard in a 100ml flask, dilute to the mark.
•
200 NTU: mix 10.0ml of 4000 NTU standard in a 100ml flask, dilute to the mark. Mix 50.0ml of above standard in a 100ml flask, dilute to the mark.
•
10 NTU: mix 10.0ml of 4000 NTU standard in a 100ml flask, dilute to the mark. Mix 2.5ml of above standard in a 100ml flask, dilute to the mark.
Warranty
The warranty period for meter is one year from the date of shipment. Above warranty does not cover the sensor and calibration solutions. Out of warranty
products will be repaired on a charged basis. The warranty on your meter shall not apply to defects resulting from:
•
Improper or inadequate maintenance by customer.
•
Unauthorized modification or misuse.
•
Operation outside of the environment specifications of the products.
For more information, please contact the nearest authorized distributor.
