What
juice? If you use 100% PG
juice then you get the most flavor, nicotine TH and nicotine irritation but thin visible vapor. if you use juices with a bit of VG in them, it will dull all of the above a bit and give more vapor. I use 80PG/20VG or 90PG/10VG in cartos. Any more VG and I can feel it degrade the drag on slim ecigs and I get less good reuse out of a carto.
And I don't know what cartos you have. if they are those SLB ones with an inner seal and fat wad of stuffing with no defined center air channel, those are not good for refilling. Bad drag IMO.