I just started making my own liquid with the help of this forum but had a question. Ive been vaping cinnamon flavors for quite a while from different vendors and have never had a problem with them in my vivi and T3. I would really like to make some DIY cinnamon liquid but I haven't seen any that are compatible with plastic tanks. Is there some brand of flavoring that I can use that won't crack my tanks? How do the vendors make there liquids plastic tank safe?