Stray Voltage?

[syncro]

Originally Posted by Mike-fish

How do you have 5vac with nothing pluged in. Any probes or " leaky" timers around

Everything was physically disconnected from the outlet.

I believe this is caused by different ground references. With nothing plugged in, the tank is not grounded. So any induced electrical charge (e.g. static electricity by brushing against the glass) will create a voltage difference. I could be wrong, I don't know this stuff that well.