I know this will seem like an idiotic question to most of you, but being new to the freshwater hobby, I am lost on this. What in the world is an air stone, what is its purpose, and what is required to get one to work? I've tried researching it online, but have come up short. I'm going to be doing a 44g heavily planted tank and would like to know if this is something I need to implement. Thanks for your help.