Well, I will tell you that I have vaped for over 3 years and personally have never had a problem with any of the protanks, or bdc heads. I guess I am just at a loss as to why you felt you needed to fiddle with it first before trying it out of the box to see if it worked?
Thats the thing, i got home, opened it up, stuck a atomizer in it, set my bat to 4v, for the 2.4 ohms, filled it with my favorite eliquid, worked great for about 3 tokes, after that all i got was a burnt taste, I tried waiting, letting the juice sit, cuz i thought maybe its just new, needs breaking in or something. Went back about 20 minutes later, tried again. Worked fine for the first 2 hits then i got the burnt taste. Took a slow drag, it started gurgling... i find theres a sweet spot to hitting it that makes it crackle, but it still has the burnt taste. After this i looked at youtube videos, read as many forum topics as I could and couldnt find a solution other than flipping over the rubber part on the atomizer. This worked for about 3 tokes, then it happened again. Came here, found the cotton wick solution.(Tore the heck out my fingers trying to get the atty heads off) Tried that, worked for about 5-6 hits, tasted bad mind you, then it really kicked in and worked great!, I was so happy, the next hit i took with a "sweet spot" strength toke, i got lung full of burnt. I dont know what else to tell ya. And i dont know the pg/vg of the liquid. Its epic juice 18mg airheads flavor. I also tried a 50/50 mix of menthol blueberry, which to my surprise the burnt taste could overpower the menthol.
Also to Mrs C, my battery died finally so I gave up.
One last edit, I only tighten it to where its giving pressure, then a 1/4 turn after that.