so how is this working for you? How far down does your air hose go?Plastic carboys for brewing come in 3 & 5 gallons and have a cone shaped induction bottom. All you gotta do is cut the top off and you're good to go.
at a 10 to 1 ratio I didn't need anything larger than a 5 really, and if I need less I can just fill it halfway. :p