Also, it's easier to remove the outer tube when it's on the battery.
I take it 'almost' off, then remove from the battery and remove the tube from the atty over the sink.
That way you don't get any juice in/on the batt.
Then push the inner tube and seal out of the outer tube.
When you replace the inner tube, inspect the coil to insure that it's not twisted or pushed down.
Also make sure all the wicking material is sticking outside the slots.
I hold the wicks down with my thumb & index finger, then install the inner tube; outer tube then top seal accordingly.