I’ve heard this argument (a titanium heater is a grounding probe) many times but I have a 3 prong titanium heater and was still getting that “tingle” when reaching in the tank. Grabbed my meter and found 13+ volts of stray voltage. I spent the few bucks on the exact same probe pictured in the thread and voltage dropped to 0000. I always attributed that “tingle” to minor cuts on my hand , change in temp from ambient air to water temp or just my imagination. Been happening for quite some time until I took the 5 minutes to test for stray voltage. I’ll never run a tank without a grounding probe again.My heater is titanium. I think it basically accomplishes the same purpose.