what kind of juice are you using (PG/VG ratio)... keep in mind, just because a coil is rated that high in theory, does not mean that its optimal performance will be on the high side... the .5 ohm vertical coils for my v2 kanger subtank mini are rated up to 60 watts, and I generally use a high vg juice (70% or more vg), the vape starts to get real warm and a bit crunchy over 45 watts - just my personal experience... I have not used the smok tank, though I have an m80 and love it... may try doing some searching on youtube for smok tct tank, see if there might be some additional info there - and just to confirm, that is not one of the ni200 (nickel/ temp control) coils you are using, correct?