I to have had many issues with Kanger replacement coils, the ones that come with the tank work flawless, however the last 5 pack for my protank 3, 2 were bad right from the box, one lasted less than an hour of casual vaping, the other 2 are in my tanks that I use daily, one is starting to taste funny and it's been only 9 days, so far only one is problem free in 9-10 days, so, I just went and got me some Kanthal wire of various gauges, some wicking and some cotton, made myself a 2.7 ohm and a 2.4 ohm coil for a a couple of protank minis, seem to work great so far, only been 4 days so we will see, easy enough though to rebuild.