Wiring advice/help needed (voltage in tank)

[gregzz4]

I have a skimmer, return and chiller pumps, 3 x 200w heaters, and 2 maxijets in my sump.
I only get 0.07 volts, so all my gear is still waterproof.
I have a crappy maxijet in my ato and it leaks 4.5v - no big deal.

Looking at your list I'd suggest you start replacing hardware as the units that are leaking voltage will eventually get worse and fail, probably blowing your gfci and turning the whole system off.

And I'd leave the probe out of the tank unless you plan on working in it.
I've never liked the idea of subjecting the critters to voltage with a probe, and only use probes in my tanks to protect me in case of a sudden failure.