Badbuck,

Welcome to Pond Boss! Over the years, there have been numerous threads posted on DIY aeration systems, so I'm guessing here. A few years ago, some members (myself included) purchased a 1.5 cfm compressor from a company, candhsales.com, for about $40. (See Bob Koerber's post in this link.)

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=30310#Post30310

If this is the compressor you are referring to, it is my understanding that this company is no longer in business but check and correct me if that is not the case.

As PondOwner stated, Ebay is one option for locating compressors.

Russ