Well I will had a kangertech subtank plus for about 2 or 3 months been using the rba since day 1. Same builds on the rba but last two days I can make a coil wick all the same from the same cotton and kanthel and give it half a day and I start getting metallic taste at the end of my hits. Same juice I always use works fine in wifes kanger mini with rba. I took the rba completely apart nothing looks to be burning or melting etc. My setup Kangertech metallic subtank plus with old dual small hole rba Kanger subox 50watt with LG battery. Running at 21.5 watts with a .5 coil 26g kanthel 5 wraps at 2mm. Japanese orgsnic cotton snug with tiny spot where I pulled the cotton back for juice to flow into the rba. Mech sauce 70/30 Any clues on what the deal is only tank I have and use daily all day. Wonder if it's just taking a beating?