Also the bags that came with mine were pretty stiff, and after a while the wrinkles from inflating and deflating would fatigue the plastic and it would leak.
They have done away with the stiff bags (at least that's what cust. svc. told me) and gone back to the Volcano (Toppits) type bag, which is what I use.

I add two screens to the crucible when I have to use ground herb. One at the bottom and one at the top (under the main mouthpiece screen). When I vape pieces though (which I prefer and what's recommended), I just use the one bottom screen that's provided. All that's gonna get down through those tiny outlet holes is a little dust, and in over two years of use I've had no problems. The electronics are not in the vapor path.