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Stability of calibration solutions
The U.S EPA approved AMCO polymer standard calibration solution is very uniform and stable.
It does not precipitate, drift or condense. It can be used directly without shaking or fliping the
vial (to make the solution even). For polymer calibration solutions that have not been used for a
long time, slowly flip the vial twice and let it stand for 2 minutes. Be careful not to shake the
solution vigorously, as this will create air bubbles which destabilize the measurement; For 0.0
NTU calibration solution, do NOT shake or flip. If using Formazin calibration solution, as it tends
to precipitate easily, each time users must flip and shake the vial to make the solution even. But
sediment can still occur during tests and make the measurement unstable. Users need to have
rich experience with Formazin calibration solutions.
4.2 Calibration Procedure (Take 0 NTU and 20 NTU as an example)
1) Instrument warm up: Power on the instrument, set parameter P2 (continuous measurement
time) to 5 times. Long press to start continuous measurement (don't insert the vial), then
wait for 3 to 5 minutes.
2) Open the flip cover and place the 0.0 NTU calibration
vial. Align the arrow on the vial lid with the one on the
sample vial holder and close the flip cover.
3) Press to enter the calibration menu, the cursor is
at 0 NTU. Press to start calibration.
4) After calibration is done, press to confirm.
The instrument will return to the calibration menu (see
Diagram on the right side). The OK sign indicates that 0
NTU has been calibrated and prompt to calibrate 20
NTU.
