I've found some very scientific discussions of aeration at HBT, although most seem to prefer a stir plate. No doubt, if the graphs are to be believed, a stirplate is much more effective. I was wondering, however, how much benefit a small aquarium pump would do for the starter. I've seen data suggesting a small increase in yeast counts. Does this imply the use of a diffusion stone (2 microns for air)? Am I correct to infer from some posts that, without a diffusion stone, the aerating benefit of a small pump is negligible?
A second question here: most people assert that it is necessary to buy a "sanitary filter." Can such a filter be replaced by bubbling the air through Star San -- much like a three piece air lock in reverse. (And I know that's not what an airlock does.) The air could be forced through the star san solution before entering the starter? I'd been imaging a yeast vial (a White Labs vial perhaps) filled with star san; the air pushed into the solution through a narrow plastic tube; then out the top from a tube flush to the lid. I'm assuming this isn't going to provide enough "sanitation." Although if my starter is covered by a tin foil lid, I'm not quite sure why not. Wouldn't it work as well as a goose neck flask to impede bacteria and particles?
And, to reiterate, the purpose is not to replace the stir plate, but to utilize a very cheap resource. I did try to google this question, here and elsewhere. Thanks in advance.