The Nautilus X is designed for mouth to lung vaping as opposed to direct lung vaping. The tank fills from the top which is convenient and easy. If you are looking for a vape tank that can help you transition away from tobacco, this tank is an ideal choice. We recommend cleaning the tank every time you change the coil. To clean the tank; disassemble, rinse pieces off with warm water, dry with paper towel, and then reassemble.