Calibration; Stablcal Stabilized Formazin Standards - Hach 2100P ISO Manual

SECTION 2,
continued
For best results, a user-entered calibration should be done every
three months.

2.4 Calibration

Calibration of the 2100P ISO Turbidimeter is based on formazin, the
primary standard for turbidity. The electronic and optical design
provide long-term stability and minimize the need for frequent
calibration. The two-detector ratioing system compensates for most
fluctuations in lamp output. A formazin recalibration should be
performed at least once every three months, more often if experience
dictates. When calibration is necessary, use a primary standard such as
StablCal™ Stabilized Standards or formazin standards.
®
For Hach turbidimeters, use only StablCal Stabilized Formazin or
formazin standards. Hach Company cannot guarantee the
performance of the turbidimeter if calibrated with co-polymer
styrene divinylbenzene beads or other suspensions.
®
DO NOT calibrate with Gelex Secondary Standards. Gelex standards
are designed for instrument verification, not calibration.

2.4.1 StablCal Stabilized Formazin Standards*

®
Most consistent results will be achieved with the use of StablCal
Stabilized Formazin Standards for calibration. Refer to Section 2.4.1.2
and Section 2.4.1.3 for information on preparing the standards for use.
Hach StablCal Stabilized Formazin in 20-, 100-, and 800-FNU values is
packaged in sets for calibration of the 2100P ISO Turbidimeter. (See
OPTIONAL ACCESSORIES AND REAGENTS on page 59.)
2.4.1.1 Storing and Handling StablCal Stabilized Standards
For optimum results when using StablCal Stabilized Standards, adhere
to the following recommendations:
•
Do not transfer the standard to another container for storage.
* StablCal Stabilized Formazin is cited as a primary standard in Hach Method
8195, an acceptable version of USEPA Method 180.1.
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