Very interesting! Thanks for the read.
Actually while the posts seem to agree that the grounding probe can divert away some stray voltage, they all claim that we should try to eliminate the source of the problem. Now, how many reefers here test their tanks with voltmeters?
As the ground probe seems to complete the circuit, I would think that it is still useable but it would be best to keep it as near to the source of potential voltage as possible like in the sump? So that there won't be issues in the main tank.
So far I have just stuck mine in the tank and my livestock seem okay, perhaps there is insufficient voltage to cause a problem in the first place. Hm