Getting Zapped

[Cal_stir]

that will work, you might have to remove the ground probe while doing tests

[mike31154]

Before you do anything else, make sure all the equipment that has anything to do with your tank is GFCI protected. In certain situations/scenarios a grounding probe can actually be a hazard & it should never be used without GFCI protection.

[Magma]

*face palm* grounding probes should NEVER be used as a fix IMO. If you have stray voltage enough to shock you have something seriously WRONG. All the ground prob is doing is letting the electricity find a path to ground, which could cause problems later on if the voltage to ground is to much. Could be a pump that has a broken seal, could be a heater but something isnt right.

Check all the equipment one at a time and find out whats causing the problem and replace it. My tank right now is measuring about 20mV which to me would be normal because of induction off the motors etc. Anything more than a few V I would start to be concerned.