How do you get the carbonation levels to an equivalent level of commercial equivalents? I have this same setup (used mostly for beer)- but when I tried to carbonate water, it was always a bit on the flat side.
We've also tried carbonating blueberries, which was really interesting. It didn't work great, but we noticed the fizziness and it'll probably be something I try again soon - perhaps using a chamber with a bigger opening than a 2L's.