Getting Zapped
 

Recently I have experienced stray voltage problems. So I looked around for info on ground fault probes. A good idea ( some don't even recommend them) I installed a DIY one and poof no shocks. But a troubling aspect of this it doesn't fix the offending problem. So tjis is what I want to do
1. use a multimeter one tip in the water and the other in the grounding slot of a plug
2. set for AC and systemactically unplug things

Is this correct way or is there a better way

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

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.

*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.

This is the exact approach that we used to troubleshoot a problem a while back.

As far as the GFCI / Grounding probe situation... I'd personally prefer a little voltage went into the tank and notice it than have something trip the GFCI while your away and have a tank crash. If I were to do it, i'd put a grounding probe in a GFCI circut and have something obvious but not essential to the tanks survival running on it. This is assuming the grounding probe doesn't trip the circuit in the first place... Or run some voltage monitoring in the tank.

If it really comes down to fish dying vs me or another human dying, I choose GFCI.

I agree, but a lot of light fixtures, T5s especially, can't be run on a GFCI.

You also have to gamble that a nuisance trip of the GFCI isn't what crashes a tank instead of a proper trip saving your bacon.

I, as such, have a combo of both unprotected and GFCI protected circuits as well as grounding probes. Who knows what's right.....