I have a Titan tank 510, and lately it's been sucking a lot of liquid out. I've tried my other cartridges and they do the same thing. I start sucking on it, it bubbles, and I get fluid in my mouth. I've cleaned the battery threading where it connects to the atomizer, I've cleaned the atomizer where it connects to the battery, I've cleaned the part where the cartridge inserts into the atomizer, I've cleaned the cartridge, and I've blown through the atomizer to get rid of all the e-liquid within it. I clean it with Q-tips, and make sure no residue is left behind. I've had the e-cig for about a month now with zero problems other than needing to inhale a little harder occasionally because the battery doesn't activate if I do, and that's only occasionally. Any help would be greatly appreciated, thanks!