I've been using single coil cartos in my DCT for the last month and every time I put a 3.0 ohm on it burns my juice at anything set over 3.7v. Although at 3.7v it feels more like 6v with how much heat and vapor there is. I thought it was a bad carto the first time it happened but I had ordered more and they are doing the same thing. The 2.0 ohm sc and 2.5 dc are working just fine on it.