A few years ago I bought plans to make the Mini-Microbulator compost tea brewer from Tim Wilson's site It is not difficult to built and the PVC piping parts are not expensive. You only have to find a suitable air pump.
A YouTube video of the brewer:
To avoid criticism do nothing, say nothing, be nothing. -Elbert Hubbard. Please critique this tiny ad:
Workee-job sucks? Quit and live the permaculture way in Montana