So my friend recently gave me a a tfv4 tank to use temporarily and i used it for a while until i noticed it started to taste harsh so i got a new coil and it was still harsh. Then i figured id go get a new tank to fix my problem so i went to the vape store and got a new baby beast and put it on and it still tasted the same as the previous tfv4 tasted which is not like burnt just very harsh and not enjoyable to hit but then i put my friends tank on my mod and it was fine. I'm really pissed, all i want to do is cape without hacking up a lung and i do n to know what to do or check or fix. please help me.