[RominK]

Okay, I found a solution online; Titanium Ground Probe
When I went to Marine Depot's site (since J & L on my iPhone is not very user friendly after they changed it), I started reading the reviews and noticed this one.

"Stray voltage is real by DOREN SMITH

Posted: 07/21/2013 from BLUE RIDGE, VA UNITED STATES

Experience Level: Intermediate

Comments: As an electrician, I was intrigued by the idea of stray voltage in my tank. All my gear is brand new and the outlet was changed to a GFCI receptacle for safety. I was VERY surprised to get a reading of over 12VAC from my water to the receptacle's ground position. So, I cut a piece of simple wire and ran it from the water to the receptacle's grd outlet and the meter then showed ZERO volts! When I pulled the wire out, the meter instantly showed 12VAC again. That sold me right there. So I have just ordered the probe because it's titanium is more suitable for long term exposure to water than an exposed copper wire of course. Good product and great price! Happy fishkeeping to all