Hello, Everyone. I am new to these forums, as well as to vaping in general. I've got an eGo passthrough (3.7v) and a Mini-Protank II (V2), as well as a couple EVODs. I really enjoy vaping, however after a couple puffs, the Protank starts producing a really nasty burnt flavor. I started out vaping a 70/30 PG/VG, 6mg wine flavor that I picked up from a local vape shop. About halfway through the tank, I could tell the flavor was definitely getting progressively worse, and by the time the tank was 3/4 done, it was too nasty to even vape. I went to re-fill it, and discovered that the liquid in the tank was substantially darker than the original liquid (Dark brown vs a light amber color). I figured I might just have a bad coil so I disassembled and cleaned the tank, then replaced the current coil with the spare that came with the Protank. I also filled the tank with a different liquid (a 60/40, 6mg watermelon flavor). Again, about 3/4 through the tank, the flavor was too burnt to continue vaping, and the liquid still darkened. Looking through the wicks at the light, there doesn't seem to be any darkened spots. I tried removing a flavor wick, which only resulted in the tank leaking and gurgling. I don't chain vape, either. I will take 5-10 puffs every couple hours or so. I figure if there's going to be an answer, it's going to be here. So after lurking for quite a while, I decided to sign up and join the community!