I purchased my ECO from 'O' ST Aquarium for $20/bag last year. If not currently available, talk to Maggie (the owner's, if I remember correctly) and she will place an order for you. That's what she did for me. This place is much cheaper than Capitol Aquarium, IMO. Good luck!!
From their website: (916) 455-6782
"O" Street Aquarium is easy to find, located just off business 80 at "N" street. we are only one block away from the off ramp. Conveniently located right on the corner of 30th and "O" streets.