I built the Sodamod because I love making carbonated drinks, the way I want them, at home. The concept was simple enough, and made a ton of sense. Adding carbonation to liquid requires releasing CO2 into the desired flat liquid. The problem with the Sodastream kits is all the simplicity, savings, and fun creating your own concoctions is put on hold when you empty their proprietary bottles. This means I have to inventory proprietary bottles, deal with shipping to get my refills, and monitor how much I’m using the Sodastream. I’d rather buy a couple cheap CO2 bottles and fill them locally, timely, inexpensively, when I need to.
I play paintball, and I have over a decade machining parts for that industry. It was simple enough for me to machine a solution that makes the price per serving cheaper. You can buy paintball CO2 tanks inexpensively online, from a local retailer, Ebay, craigslist, etc. The question is now eliminating the need to reorder and stock Sodastream tanks. If you don’t have a local vendor that stocks Sodastream tanks, more than likely you do have an industrial/construction gas supply house like Airgas. You’re more likely to have a sporting goods retailer and/or a paintball retailer that can refill your purchased paintball tanks.