You can find some at Deathmart in the Seattle area.... but you are much better buying online as Mike suggested.
Eheim Pimp #104!
46 Gallon corner tank, 220 watt cf, custom canopy, co2 w/controller.
20 Gallon, 110 cf highlight tank, co2 w/controller.
18 high 24 watt cf, 36 watt ODNO ghetto paintball co2 setup.
60 Gallon river tank, .5 gallon nano tank, and 8 other tanks for fish and propagation.....