Cartos and carto tanks just never really worked out for me. I can never get them to work the way I hear people rave about. Maybe I'm just dumb and keep messing it up, but I just give up on these for now. I don't like the taste of the poly fill either, and I always seem to get dry hits and they aren't full of flavor either. I've tried the cap filling and syringe and pushing the juice into the carto from the side and etc., just never really impressed me. I like clearos because I don't like how disposable cartos seem, I like they way they look, I like the ease of filling them and that they are easy to clean.
But clearos aren't that reliable either... they always seem to work great at first but then you just get tired of dealing with all the mishaps. Like the T3s for example. They worked great when I first tried them and I thought I'd never have to look for anything else. They were affordable, looked nice, simple, and seem to give much better flavor and vapor than any other clearo I've used before. But noooow... they leak, gurgle, flood, give inconsistent hits... I've tried new heads and cleaning them but they just keep getting blah over time. Wish there was something a little more... permanent and just WORKS!!