They are connected to a gfci

As I understand it, a grounding probe works in conjunction with a GFCI. The grounding probe will tell the GFCI if there is any leaking voltage. Otherwise there is no ground for the stray voltage until you touch the water which may then provide the ground.
I use both a probe and a GFCI.

Mitch

i heard using both probe and GFCI will kill you...
Why does everyone have conflicting messages!

i would also add the powerhead is a new tunze 6105 and i have faith its not broken.

Last time I checked I wasn't dead.

Mitch

Now watch some expert come on here and tell me I should be.

Mitch