I have written a blog that goes into some detail on the anatomy of a cartotank at the end of this article:
http://www.e-cigarette-forum.com/fo...k-what-primer-juice-delivery-attachments.html
I've also written a cartotank tutorial, with included videos on how to fill and assemble one, and an excellent video done by reviewer PBusardo on cartotanks in general.
http://www.e-cigarette-forum.com/forum/blogs/baditude/3710-5-cartomizer-tank-setup.html
For me, cartotanks have been my go-to juice delivery device for several months. I have found that they provide me with the best flavor production, are extremely portable and durable for on the go, and are not position dependent like string-wicked delivery devices like clearomizers and Vivi Nova tanks are. If the tubes are made from pyrex glass or polypropylene plastic, they are safe to use with the tank-killer juices such as cinnamon and citrus flavors.
There is a slight learning curve involved, and they take a few minutes longer to prepare than a simple clearo takes, but they are worth it. Just follow known methods of filling and assembling them, and not stray from those, and you will find they are an excellent delivery device.
I keep a dozen tanks up and running at any particular time, each with their own flavor. I typically change between tanks 3 -4 times a day because it is so easy to change flavors this way.
Additional articles I've written can be found in the link under my avatar.