For calibration of Conductivity (EC) meters in Hydroponics

DESCRIPTION:

BACKGROUND:

Important: Poorly maintained electrodes can upset the linearity (i.e. ‘slope’) of the readout values either side of the Conductivity Standard’s value. Thus it is essential to clean the electrode with Electrode Cleaner prior to calibrating.

Conductivity meter electrodes normally become coated with impurities. The degree to which this occurs will depend upon the nature of the samples being tested. It will also depend upon whether or not the electrode is rinsed with distilled water and properly stored after each use.

Electrode contamination causes a decrease in the effective surface area of the electrode exposed to the solution. This will lead to lower values being recorded, unless frequent calibration is performed.

When correct practices are followed, quality conductivity equipment needs calibrating only a few times per year.

An indicator of the need to clean is given by the extent to which the meter drifts out of calibration.