not one at all. using 3mm silica wick. this is my 2nd .8ohm coil working gorgeously. you just need to build it nicely. also i find that if i fill the
tank to full regardless of the coil ohms i get dry hits on any coil. the protank for some reason wont feed when the tank is full. so i fill about 3/4 now and have no issues. if you find your getting dry hits unscrew the base a bit until you see bubbles come up. once you see bubbles come up tighten it up a hair and you should be good to go. i rarely have to unscrew the base out but when using really thick
juice you might. dont use any additional flavor wicks not needed with 3mm silica. not even with 100% pg. i find i get flooding when the tank gets down really low then i know its time to top it up. i will upload video to youtube and try to show you.