Started with 10%, than bumped to 15%
So you liked the Blueberry better than the Kiwi, eh. Myself, was that opposite. Now, however, I like the Kiwi mixed with Pineapple. Or, Strawberry, by itself, is really tasty.
They also have this highly concentrated "cooling agent" Liquid where all you need is one to two drops per tank, and the flavour becomes totally refeshed. Much more so than a minty Menthol flavour.
I made the "mistake" of testing a drop of it on my finger and then taste tested it. Well, my tongue was nearly frozen for 10 minutes. Crazy stuff.... who knows what it's actually derived from. I'm afraid to ask