I am Vegas,I and my uncle use the exact same device(Atlantis with 0.5ohm coil),his e-juice never turn dark and the tank never get hard draw,I use sweet juice as well.My tank has a hard draw and burn taste at 1-2days,but his only gets after a 2 weeks of high vg juice.I am really confused.
I talked with my uncle,he said that the problem may stems from how hard I am pulling on it.We may have experienced this when we smoked and people bummed cigarettes from us.some people take such a hard drag the filter disintegrates a bit and turn dark brown almost immediately.
Conversely some of us could smoke an entire cigarette and have the filter just turn a light-yellow-golden brown color by taking a longer,much softer softer drag.
Harder draw means more air and more air=more heat=caramelization
If he is right?