I am transitioning to paintball co2 bottles instead of refilling sodastream. Not sure if it will work, because so far it appears they were afraid to fill me with hardly any liquid at all. Anyway I will recount my journey for others to either comment on or learn from my mistakes. We need not use pricey sodastream proprietary syrups (http://www.homebrewtalk.com/f95/bett...stream-396003/
) or co2 refills, even though they have apparently "boobytrapped" their tanks to prevent easy refill.
1) First I tried to play ball with Sodastream. Of course they didn't offer tank exchanges where I bought them, but they did list Walmart and Bed, Bath, and Beyond as sources. Online I could confirm that Walmart had no exchange tanks in stock in any available branch and that they could not be ordered. I eventually checked a branch of BBB that sodastream didn't list and they now offer exchange for $20. Someone on this site said $5 coupons from BBB site are useable, although I haven't seen such coupons even after registering.
2) Someone here mentioned co2doctor.com as a source of paintball adaptor valves, which I ordered. Later I found you can google paintball sodastream and find many vendors for about a $50 device. They give a bunch of advice and offer alternatives like replacement valves to allow easy self refill of sodastream bottles. Some site said the boobytrap can also be overcome just by slow filling (with liquid, not gas c02).
Anyway, the valve is kind of intricate and needs adjustment of a kind of setscrew. In practice runs on an empty bottle and even the first time on a full one, the thing malfunctioned on me and got jammed both going in and backing out. It seems to be very sensitive and you have to stop turning (and back out 1 turn) at the slightest resistance. I think when I overdid it, it slips beside the co2 valve and jams. I don't call it a defect though, and the vendor encourages calls for assistance. I'm just saying it's an unfamiliar world with pitfalls in not knowing how what is tight enough all around.
3) I bought a 20 oz paintball tank for my fizz model sodastream without being sure it would fit internally because I had to use an online credit fast before expiration. One site said my fizz was limited to 12 oz size, and another said 20 oz. I saw a picture appearing to be fizz with a 24 inside, which I later I saw listed as better. The only really convenient refill site only charged me $3.50 for a 20 oz fill which is a bit bigger than my sodastreams. They said they underfilled it to avoid overexpansion in transport, and I had to fill out all kinds of paperwork to promise to not carry it in a hot car, etc. At the register I had to show ID and sign god knows what about not being a sniper or something. I don't feel any liquid sloshing around when I tip it and it doesn't feel much heavier, so wonder if I need to get one of those (larger) tanks with a temperature driven "fill level" gauge on the side?
Anyway on the second attempt, I got the setscrew right and when using it I got kind of a softer than normal blast of gas. Maybe that is the way the valve affects things by making a longer twisted path to the soda bottle? But it sounds a lot like when the liquid co2 is about used up and I'm coasting on the last dregs of gas. My Fizz model has a useless pressure gauge that never gives warning... it read max full when my last sodastream tank was clear as day in it's last gasp (it also uselessly marks all soda drink bottles as zero or the lowest level fizz, and the latter only when it is insanely bubbly). Hoping for the best, but preparing for expensive plan B's...