Are we only listing fish stores on that page?
FWIW, I find the following two places invaluable:
(For CO2 refills)
Carbonic Service
1920 De La Cruz Blvd
Santa Clara, CA
408-727-8835
www.carbonicservice.com
(For all kinds of plumbing parts that OSH and HD don't carry)
Ewing Irrigation
1735 Rogers Ave
San Jose, CA 95112
(408) 436-8848