I love my ProTank2. That being said I had a few of the same problems you did that almost made me ditch it and look for a carto tank. First problem was a leaky tank, turns out when i cleaned it one of the O-rings popped out and I didnt even notice. Then I had a bad draw issue like this, the fix that worked for me was buying a new base for it. Apparently I overtightened a coil at some point or another and stripped part of the top thread of the base out so when the coil was tightened the air holes didnt line up. Of course that took a week for me to figure out, but while i was researching my problem I came across a post that said Kanger was having a QC issue with the bases at one point(maybe you got a dud), a number of them werent threaded to spec with the coils so they werent lining up with the coil right. Usually if you can unscrew a bit and draw, a bad base is probably your issue. You can find base replacements for $1-$2US at a number of online vendors.