I never noticed before, but I realized recently my coil's aren't making contact with the battery, so it appears that my tank isn't working. I've got two Kanger bottoms, a Kanger Pro tank 3 & and a Kanger Aero tank. They're supposed to be interchangeable, but while the bottom of the Kanger Pro Tank 3 is open, the bottom of the Aero tank is not. The bottom of the Aero tank sticks out past the threads & I haven't had a problem with it making contact & working. I was thinking maybe the Pro Tank 3 bottom for whatever reason isn't allowing me to seat the coil fully into the holder.
See how the bottom of the coil doesn't extend beyond the thread? Is that normal?

See how the bottom of the coil doesn't extend beyond the thread? Is that normal?