Hot Tub Trips GFCI instantly

[Gregc73]

I bought a used hot tub off of craigslist and am setting it up to make sure everything works. I connected the wiring from my old hot tub, however, as soon as I flip the GFCI, it trips. I disconnected the heater and it doesn't trip. I did the ohm testing and it is 11.5 when I test the leads and 0 when I test the lead to the outer sheath. I believe that indicates everything is OK. However, do I ignore the testing at this point and just assume it's a heater element issue since that is definitely what is causing the trip? There is some corrosion at the top of the element near the leads...could that be causing the short? I've attached a picture of the leads.

[attachment=0:3g6ibewr]IMAG0281.jpg[/attachment:3g6ibewr]

 

[Gregc73]

Luckily, this took the same heater element as my old hot tub, which was fairly new. I swapped the one from the old tub into the new(er) tub and it now powers on without issue. Here's hoping this is the last of my surprises with this thing....