I still use silica but also do micro coils with cotton. I like the ease of changing wicks with cotton but I saw a video on utube that said if you try to dry burn a micro coil on a ProTank or Evod you will melt the rubber insulator. Is that true? I wrap my micro coils at 1.8-2.2 ohms. Seems that my favorite flavors are the dark ones and I dry burn my silica coils often.