That's a negative to all the replies you got. It's not an opinion but a fact that the design is flawed. I've been using the Titan Tank for a month and it kept leaking on me. I thought it was the model and decided to upgrade. I went with the egoc and it's doing the same. I've come to the conclusion all tanks do that. If you watch the tank carefully when it's full to the recommended fill, it will seep from the sides. There are holes on each side of the tanks. I'm guess it has to do with air flow. I don't buy into that dragging too hard or fast theory. It's the tanks that are flawed. Trust me!!! You can see for yourself. When it leaks from the side vents, it seeps down to the atty and leaks out.. No, actually that's just your opinion, not a fact. This may be why you're still having problems then.
I'm not saying there's not room for improvement in the design of the tank systems, but I wouldn't say there's a major design flaw. I'm sorry you're not getting on with the tanks, and it's true they're not for everyone. If you would like, we'll all be happy to help you try to figure out what's going wrong. But I can tell you I've been using the Tornado Tanks since TW first starting selling them, and it's my opinion
that there is no major design flaw. Once I learned how to adjust the way I vape to better suit the tank system I've had very little problems. Sure, you will get a duff atty from time to time that, despite your best efforts, will run too rich or too lean, but most problems that people encounter with the tanks can traced back to something they are doing (or not doing) with regards to maintenance or assembly, or to their vaping technique.
Yes, those vent holes in the side of the cart are air channels. And as Ms. Puffer pointed out, the moisture you will see from time to time in the top part of the cart, although it looks just like the juice you're vaping, is really just condensation that gathers there from the vapor. If you flood the atty bad enough it is possible to suck juice up into the top part of the cart, but again, this us usually down to a warn cart cap that needs replacing, or due to an overzealous vaping technique.
And as far as the Tornado eGo-C in concerned, I've been using one since the end of November and haven't had one single leak, flood, or ever had that "burnt atty" taste (except for one time when I wasn't paying attention and vaped it bone dry, and I can hardly blame the tank system for that). The "C" just flat outperforms everything else I've ever vaped, and I'm just a bit baffled as to why you are having problems with it.
The only thing I can think of is that maybe you are using one of the blank carts that came with the kit. These have an odd cap on them. It's hard plastic, but built like the soft caps (sits down deeper in the cart) and is very difficult to remove. I wonder if maybe you damaged the cap or the cart trying to get it off (I completely destroyed both the cap and cart doing this on the first one I tried to use, and just threw out both of them), and that's causing the leaks. If this is the case, and you have no other carts, just use one of the pre-filled carts that came with the kit. You can empty them out if you don't like the tobacco flavored juice (that's what I did).