OHAUS ST20M Series Instruction Manual

Welcome to OHAUS!
After more than a century of perfecting the art of measurement through our durable weighing
products, OHAUS precision is now available in a line of portable electrochemistry products that
provides accurate measurement of pH, ORP, conductivity, TDS and salinity.
ST series pen meters are the economical option when you are simply looking for meters that are
easy to use and provide accurate measurements.
The pen meters should not be used by Children of age 12 or younger.
This product conforms to the RoHS Directive 2011/65/EU and the EMC Directive 2014/30/EU.
Thank you for choosing OHAUS waterproof pen meters. Please read the manual completely
before use. This manual serves the following models:
• ST20M-B (pen pH and Conductivity meter)
• ST20M-C (pen pH and Conductivity meter)
pH: Condition the pH electrode by immersing it in pH electrode storage solution (3M KCl
solution) for 1 hour before using. If the pH electrode protective cap is dry (may cause white
crystals), add storage solution in the cap and soak the pH electrode for 1 hour.
Conductivity: Rinse the conductivity electrode with pure water (distilled water) before using.
pH: ST20M has a 0.01 pH resolution and 0.05 pH accuracy and is factory calibrated.
You may need to calibrate the ST20M regularly to ensure the pH accuracy.
Conductivity: ST20M pen meter is factory calibrated, and requires calibration every week for
both pH and conductivity.
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ST20M Pen Meter
Instruction Manual
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