[mike31154]

In the first post, the OP said he felt a tingle until he removed the grounding probe. If current was flowing from a piece of faulty equipment through the probe to ground, he shouldn't be feeling a tingle. This makes me suspect that he may have a faulty receptacle (or wherever the grounding probe was 'grounded') and that this is actually introducing a voltage potential into the tank and when he put his hand in the water, becomes the return path. This is why I suggested he investigate his house wiring.

But again, yes, I don't personally use grounding probes because their presence can actually hide or mask a problem all the while giving you a warm and fuzzy because you have one installed. Power can be a funny character, lots of gremlins in the wiring. GFCI is the way to go for your personal safety.