I've been having the same problem with my dark tobacco and coffee juices. I use cartos on my REO and carto tanks on my Provari. Either system has problems with dark juices. Last time I bought cartos, I got clear ones so I could see what's going on inside. After all-day
vaping my favorite tobacco
juice, the stuff inside the polyfill actually turned coal black! Taste dropped off sharply. I could still get vapor (100% VG), but no taste. Just ordered my first RBA, hopefully that will fix that problem. Of course, my worst and nastiest juices all flow beautifully.
