Ph Probe Problem

To: Aquatic-plants at actwin_com
Subject: Ph Probe Problem
From: Andrew Hamilton <andrewha at tafe_sa.edu.au>
Date: Wed, 8 May 1996 08:57:12 +0930

Paul Krombholz replied:

>On the other hand, you might be able to compensate your system for the
>altered reading.  I am assuming that the output from your pH probe controls
>some kind of CO2 injection system.  If you assume your pH readings are 0.4
>units too high during the day, and you want the pH to be kept at, for
>example, 7.0, can you adjust the set point to inject CO2 if the pH is 7.4
>or higher?

Paul, this wont work as when the lights turn off the magnetic field
disappears therefore causing a variance in the Ph reading. I am using a
Dupla Microprocessor as the controller and this records all fluctuations in
Ph so it can try to improvise for fluctuations. Eventually it will stop
injecting Co2 during the day to make up for the Ph drops at night. (So Im
told by the Dupla guys). I tell you, if its not one thing its another.

Andrew
The Adelaide Zoo has just agreed to spend 40 000 dollars on two new tanks
for the native fish displays.