Bluelab Guardian Monitor - Manual (Page 8)

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8
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10.0 Calibration
pH calibration is required before fi rst use to ensure that the fi rst reading is
accurate.
• The Bluelab Conductivity/Temperature Probe DOES NOT require calibration.
• The pH of the Bluelab Guardian Monitor DOES require calibration.
For accurate pH readings the pH probe is cleaned and recalibrated when:
• The reading is different to what you were expecting.
• The Guardian Monitor is reset to factory default.
• The pH probe is replaced with a new one.
• It has been a month since the last successful calibration and hte calibration indicator
lights are fl ashing.
When calibrating the pH after fi rst use the pH probe needs to be cleaned. See pH probe
cleaning in section 14.0.
For best pH calibration
pH reading accuracy is dependant on the accuracy and age of the calibration
solutions used, and use and cleanliness of the pH probe tip.
• Ensure the pH probe has been cleaned and rinse the pH probe with clean water
between calibration solutions to reduce contamination of the pH solutions.
• Only fresh uncontaminated solutions should be used.
• Calibrate the pH at the same temperature as the solution to be measured.
• ALWAYS calibrate the pH probe with pH 7.0 then pH 4.0 or pH 10.0.
NOTE: The conductivity/temperature probe does not need to be calibrated, but must be
cleaned to remove any build up of nutrient salts. See Section 13.0.
The pH calibration involves cleaning the pH probe tip and then calibrating in TWO
SOLUTIONS.
If a reading below pH 7.0 is expected, use pH 7.0 and pH 4.0 calibration solutions.
If a reading above pH 7.0 is expected, use pH 7.0 and pH 10.0 calibration solutions.
Follow the steps on the following page for Guardian Monitor pH calibration.
Storage and use of calibration solutions
• Always place the lid back onto the bottle after use or evaporation will occur rendering
the solution useless.
• DO NOT measure directly into the bottle. Tip a small
amount into a clean container and discard after use.
• Never add water to solutions.
• Store in a cool place.
pH reading accuracy is dependant on the accuracy
and age of the calibration solutions used, and use
and cleanliness of the pH probe tip.