URGENT PLEASE HELP ! Shock everytime I put my hand in the tank

[gregzz4]

Getting shocked only sometimes could mean the faulty hardware is something that only runs sometimes, such as a heater


Something else I wanted to touch on, but after the multimeter stuff ...

You have a ground probe and are getting shocked.
Does this mean you don't have a GFCI ?

Using a probe without one is much more dangerous than not using a probe at all. You are allowing the water to become fully energized (completed circuit) from a voltage leak but doing nothing to protect yourself

If you are using a GFCI, test it