Just to contribute a bit. If I'm not using my carto/tanks, then I'm using a Vivi Nova. tilt and rotate. Some people (that I've found) just cant get the grasp of priming the carto. They all think that about 4-5 drops and it's all good to go. When I show em how to fill and prime a carto, well they don't understand where all the juice goes. (IMHO they shouldn't be using a carto. They saw one and thought it looked cool). Sorry just my 
