Do I need to ground my sinking water trough heater in my metal water tank? 
I keep hearing about adding a ground rod to water tanks, but does that only apply to the Rubbermaid troughs?
No, you don’t have to ground the heater. The heater is grounded by the ground wire in the plug. To accomplish this: the extension cord and all connectors must have the ground wire in good shape. I would recommend you plug the heater into a GFCI outlet to protect yourself should any of the wiring or heater fail.
Grounding the tank is a band-aid over an underlying problem.
Okay, stupid question - how can I tell if my outlet is GFCI?
It will have 2 buttons between the plug ins. One button says “test” the other “reset”. The ones I’ve had are red/ yellow in color.
That way if something goes bad with the heater it will trip the button and kill the power to the outlet.
Perfect. Thanks! 
