For one, if you are getting "smoke" from the tank, you have bigger problems. You should only get vapor. It's either not wicking juice very well, the ohms are too low, the wattage is too high or the coils are burned. You shouldn't get smoke if it's working properly, only vapor. Also, the harshness could be either the PG is too high, or the nicotine is no good. I bought some nic a while back, and it was real peppery. Even at max VG, it burned like hell.