You didn't put anywhere near enough juice into the cartomizer. This is the
most important step in setting up a cartotank, called "priming". The carto needs 25 - 30 drops of juice to be adequately primed before putting it into the tank. The filler material has to look like a wet slushy drink when it's ready.
My guess that firing on that dry carto has already ruined it - it's going to taste burnt and you'll never get that taste removed no matter what you try. Start fresh with another carto. (You are using cartos that have holes in the side, correct?)
Here's a cartotank setup guide that I made for new tank owners. Do exactly what I do and you will have a great running cartotank. It includes a link to a video demo that uses many of the steps that I use:
http://www.e-cigarette-forum.com/forum/blogs/baditude/3710-5-cartomizer-tank-setup.html
Once a carto is properly primed, the carto will be replenished with more juice from the tank each time you take a drag from your tank. You will be able to refill the tank, with the same carto, multiple times. The setup guide explains how to do this, too.
Once the cartomizer starts to have a stiff pull, it's time to replace that carto with a new one. You should be able to use 25 - 30 ml of juice through each carto, depending upon juice viscosity and juice color (thicker and darker juices decrease carto life).
You will also need to purchase a tank tool to make life much easier for you and your tank. I highly recommend the Slap Yo Moma tool from Big Daddy Vapor. I have a video of PBusardo doing a review and demo of it in the above blog article. It's the best investment that I have made in vaping.
