Not sure if this is in the right section but I bought a subtank (full size) about a month a go and this morning I thought it was about time to change the coil so I decided to build my own rba using the prebuilt coil heads that came with it, they shoot at 0.5 ohms so I'm happy with that and thought it would be a good place to start with building my own, how ever back to the point, both my istick and itaste will only recognise the subtank with the beauty ring on the bottom of the tank which I find a bit strange, is this a common thing with the subtank?