Bak Pak airstone mod air pump

[gparr]

I'm trying to do the airstone modification to my Bak Pak. I bought a Coralife limewood airstone but am not sure how big of an air pump I need to drive the stone. What air pumps are people using?
Gary

 

[trido]

I use a "Million Air M-100" I like Lens' Idea of using a larger adjustable one though. I feel like mine could be just a little bigger.