GardenBanter.co.uk - View Single Post

08-09-2005, 03:36 PM

In article ,
says...

Hi

I have what I think are some odd things happening in my tank.
... When the lights come on the Ph
will drop to about 5.9 and steadily creep up during the day to maybe
6.1. When the lights go off at night the ph then shoots up past the 6.5
limit and the controller then starts injecting co2 overnight keeping it
around 6.5. As soon as the lights come on again in the morning the ph
drops again to 5.9 ish????

Is it possible that some electrical interference from your lights is influencing
the pH measurement ? I suggest a quick test. While watching the pH readout on your
controller, turn the lights on and off. Is there an instantaneous change in the
reading ? If so, then there is an influence on the pH measurement due to the
lights that will cause problems.

A while back I experienced this with a handheld pH meter and power compact lamps
with an electronic ballast. I posted on the subject and others said that there was
no problem with their controller. The Sera is not as common though. Nobody with a
Sera responded to the post, and your installation could be more sensitive.

If you find this to be the problem, one thing that you could try would be to
separate the pH probe and cable from the lighting wires and ballast. Also, try
grounding the reflector(s). If the reflector is a problem, you will be able to see
a change in pH readout when you touch it. When you have it solved there should be
no change in displayed pH when the lights are turned on or off.