http://www.popsci.com/diy/article/2012-06/how-make-your-own-home-carbonation-system
Excerpt:
“Sodastream machines are nice, but for the true seltzer addict, a do-it-yourself carbonation system can be cheaper, more flexible, and more fun If your friends and family are anything like mine, you’ve observed that home beverage carbonation is experiencing a bit of a renaissance lately.”
tariq.ca 