Metex 8760CLP Total Free Chlorine & pH Analyzer - Manual (Page 32)

AQUAMETRIX INC.
1-800-742-1413 www.aquametrix.com 32
pH and Temperature impact on Chlorine
The measurement of the chlorine concentration is done by the galvanic sensing electrode. However, the
chlorine chemistry of the sample will change with both temperature and pH. Illustration 15 shows how
the relative concentrations of hypochlorous acid and hypochlorite ion shift with a change in the water
pH. This same relationship is also dependent on the temperature of the solution, as the curves will shift
with changes in the temperature. The 8760CLP includes a temperature input and pH input to
compensate for these changes. A pH sensor is provided to measure the pH of the sample and
temperature compensation is provided via a temperature sensor in the chlorine electrode.
A method has been provided in the analyzer program to change the compensation method for
temperature compensation and pH compensation from automatic to manual. Providing a method of
manual temperature compensation and/or manual pH compensation allows the analyzer to continue
measuring free available chlorine and total free chlorine in the event that the temperature sensor and/or
pH sensor are malfunctioning or absent.
Manual Temperature Compensation
From the main menu, select [tFCl] [tc]. At this point either [Auto] (for automatic temperature
compensation), or [SEt] (for manual temperature compensation set-point) will be displayed. To change
the setting from [Auto] to [SEt] press ENTER to edit the current setting. The display will start blinking,
indicating that a selection needs to be made. Use the Up or Down arrow key to display [SEt]. Press
ENTER to select manual temperature compensation.
With [SEt] as the current display, press SELECT to display the temperature setting for manual
temperature compensation. If the current value needs to be changed, press ENTER to edit the current
setting. The display will start blinking. Use the Up or Down arrow keys to display the desired
temperature for manual temperature compensation. Press ENTER to accept the currently displayed
value.
Manual pH Compensation
From the menu select [tFCl] [PH.C]. At this point either [Auto] (for automatic pH compensation), or
[SEt] (for manual pH compensation set-point) will be displayed. To change the setting from [Auto] to
[SEt] press ENTER to edit the current setting. The display will start blinking, indicating that a selection
needs to be made. Use the Up or Down arrow key to display [SEt]. Press ENTER to select manual pH
compensation.
With [SEt] as the current display, press SELECT to display the pH setting for manual pH compensation.
If the current value needs to be changed, press ENTER to edit the current setting. The display will start
blinking. Use the Up or Down arrow keys to display the desired pH value for manual pH compensation.
Press ENTER to accept the currently displayed value.