Does anyone else have problems using a bottom coil tank such as a Protank on their vv/vw device? It seems like every coil I put in my protank tastes burnt regardless of what wattage I have my zmax on! My vivi nova works fine. I'm wondering if their is a problem with the device or if I got a bad bunch of 2.5 u heads. Ive tried removing a wick, but nothing seems to change. Any help would be appreciated!