Ultra-Life Controller

>> From: "Jim Viscosi" <skribb19 at borg_com>
>> Date: Mon, 10 Feb 1997 07:05:22 -0500
>>I bought an UltraLife pH controller about a month ago.  I notice that
>> when I turn the tank lights out at night (3 flourescent tubes), the pH
>> reading will instantly jump from say 6.84 to 7.8 for a second,
>> triggering the CO2 to come on for about 15 to 20 seconds.
>> Anyone have a clue to whats happening here, or better yet, a
>> suggestion? This didn't happen in the first week of use.
>We don't have the Ultralife pH controller but we do have two Ultralife
>temp controllers.  One works fine but the other exhibits much the same
>behavior.  When it turns the heating cables on or off, it gets in the
>mode of:
>1. cycling power causes the temp reading to change
>2. the new reading causes the controller to cycle the power
>3. goto to 1.
>The end result is a lot of relay clicking that I, fortunately, can't
>hear.  Really bugs my wife, though.

I had the same problem with the Ultralife pH controller. A friend of mine 
suggested that the coil in the valve was attempting to maintain its 
magnetic field when the controller switched it off. This apparently results 
in either a voltage or a current spike which, in turn, screws up the 
controller. To fix the problem, I put a varistor (Radio Shack, ~$2.00) in 
parallel with the coil. It works for my set up. It may work with the 
heating coil and the flourescents too.

If I didn't get the electrical details right, could someone please 

Waterloo, Ontario