I just bought a whole CO2 system myself.
I bought a Milwaukee 957 from
http://www.thatpetplace.com/ - BUT I called them to do a price match with
http://www.tsunamiaquatic.com/catalo...43/2982460.htm . I got it for an excellent price, from reliable company, and they had it in stock. Plus they answered the phone when I called.
I got my CO2 cylinder from
http://www.beveragefactory.com/draft...anks/co2.shtml .
Here are my costs:
Ten-pound aluminum cylinder at beveragefactory.com: $90 (including shipping)
Milwaukee regulator at thatpetplace.com: $79 (after price match)
Drop checker at thatpetplace.com: $10
Shipping for thatpetplace.com: $11
CO2 refill at local Fire & Safety company: $15
Total for brand new pressurized CO2 system: $205
This is for a complete CO2 system for a 100 gallon tank. For a 15 gallon tank a 5-pound CO2 cylinder would probably last you a LONG time.
Oh yeah... I just used a micro air stone as a CO2 reactor, it's cheap and works fine:
http://www.drsfostersmith.com/produc...22&pcatid=3722
http://www.bigalsonline.com/ is having a big 10-30% off sale going on now, so you might check out their prices too.