I decided I could no longer wait another 4 days to receive this replacement O-ring so I vape-gyvered my own using the ringed rubber from the base of a condom. I swear this thing isn't leaking whatsoever now. I have turned it upside down, shaken it, laid on it's side for an extended period of time and the seal is perfect. I still recommend replacing with Kanger brand O-rings, however if you are ever in a pinch and waiting on shipping give it a shot, works great. If just cut a tiny bit or poke a hole right above the base of the condom, then you can easily tear the rubber ring right off. Then cut the rubber ring and place down into the gap so you can measure what the length should be. Mark it with your thumb and cut it a tad longer than you think you should as you can always snip tiny pieces off with finger nail clippers until you have the perfect size. I just cut mine so it was flush against the inner metal and it works perfect. Also shouldn't have to worry about it being non-food grade (for obvious reasons). This should be used primarily on the top part of the protank (above pyrex/glass
tank) probably not the bottom although I haven't tested it. If you lost the top one I would move that to the bottom portion.
The reason I was forced to come up with a solution for my v2 Protank is because my v1 is just not cutting it anymore. Not getting any flavor from my liquids and the tastes are all off all the sudden. After closer inspection, the silicon rubber ring on the base that screws off the bottom of the unit to refill is discolored and all funked up (pic below for reference). BTW...this is not the O-ring I replaced from the above paragraph, but the one around the threads where you screw your coil unit into.
Guess it's true what they say about certain e-liquids being somewhat caustic as that ring now looks all haggard and is being eaten away. It is really the only thing I can think of being the source of the v1's issue, but the taste of my vapes is just OFF. It's def not my coils as I have tried new 1.8's, 2.2's and 2.5oHm coils in it and get the same result. Really weird. Can't take the v1 apart, so if replacing that ring doesn't do it then I just won't use it again. I won't ever vape this hellish key-lime cheesecake juice I bought and let steep a month. The single nastiest stuff I have ever had and I prefer to blame that stank nasty juice rather than myself for tightening the base to hard (which is also a possibility). I do know that it is the ONLY juice that I have not been able to get the smell off of metal parts using only hot water, had to soak in 91% alcohol for a half day before it went away. Oh well.....I also have some strawberry cheesecake that tastes like I just sprayed strawberry air freshener on my tongue. Foul stuff. Left the caps off of it for 3 weeks thinking for sure that some of that stuff would evaporate off.... I was wrong. Sometimes you just learn that some vendors just sell some straight up nasty tastin' stuff. The blueberry cheesecake from the same vendor is amazing, so not sure what's up with all that.