Aloha,
It's awesome that you knew how to check it by unplugging things one by one.
One difficulty I have with grounding probes is that when electricity is grounding into the tank it goes to the Ground and the hobbyist may not feel it with a shock. Undetected, the electricity runs through the tank for who knows how long, possibly causing weird problems with the animals.
I've seen some awesome looking tanks with grounding probes so please take what I say here with a grain of salt. (pun intended
) As a matter of fact, today my wife and I saw DMowers awesome tanks. I didn't ask which ones had grounding probes, but it didn't matter. They were all awesome.
Another difficulty is that grounding probes also disrupt the operation of GFI outlets, though I recommend GFI's for lights and heaters only, not pumps. We don't want pumps shutting off for any reason other than a real emergency, a problem that has happened with hobbyists here who lost a lot of animals when the water stopped.
Mahalo,
Mark
Edited by Mark Peterson - May 18 2013 at 5:28pm