I performed an experiment yesterday just out of curiosity with a V4L premium watermelon 36mg carto & 2nd gen V4L premium blank carto. Since day 1 when I got my ultimate ultimatum kit I've noticed that no matter how low the nic level of V4L's PG cartos were the TH they gave was always WAY too much for me & friends that I have gotten started vaping with V4L. Yesterday I decided to do a reverse Taryn spin on the watermelon cart to test if the massive TH was from the juice or the cart or both. Having extracted the watermelon juice I refilled the emptied cart with some 12mg Tasty Vapor blueberry 70%VG / 30%PG & that undeniable TH was still there, needless to say that got trashed immediately. I then took the 36mg watermelon & cut it 1/2 & 1/2 with TV blueberry & refilled the blank premium carto with it. The TH was still there, but tamed down some by the blueberry. However after vaping that cart to the end I found much to my disgust that the bottom of the carto was covered in green oxidization just like you would find on old pennies. WTF is this about? I've been refilling cartos for about 1 1/2 months now & never saw anything like this w/ Halo, Tasty Vapor or Alien Visions juice. Has anyone seen anything like this before & if so what does this mean for V4L PG juice or cartos?8-o