cracking

Hi Guys, I have a Smok Alien Mod and using a TVF8 tank with it's coils. I usually smoke on 130w but when i smoke on a lower wattage and sometimes on the same wattage i hear a boiling / cracking sound. The only time i dont hear the sound is when i pull really really hard. A few friends of mine...

Hi everyone, looking for any suggestions as to what might be going on... First, this is a frequent customer whom I believe. Two, I know these are genuine isub tanks (the original one with a plastic tank and driptip permanently attached) and we've never had this problem before. Three, it was not...