i've used organic cotton balls, cotton cellucotton, Japanese cotton, and even rayon cellucotton (which i am actually impressed with). Never really had gurgling or flooding or for that matter even any leaking. I even took out the "tube" in the deck to improve airflow. I think the secret to this tank is making sure you put just the right amount of wick sticking out/through. Not too much wick to choke the coil and not too little allowing juice to seep through the chimney holes. Sort of a learning curve to get it right. Once you have it is a dream... prob my favorite tank