So, here is a recipe for a diet grapefruit soda. I call it Frasca, because a) the name is close enough to that commercial product without blatantly violating copyright, and b) just call it a tribute to the designers and manufacturers of those fine Frasca general aviation flight simulators.
Step 1: Acquire Foodstuffs and Tools
1 medium grapefruit
2 cups Splenda or other suitable sweetener
SodaStream straight-up seltzer
Hand or sieve
spatula or other stirring tool
Step 2: Make the Syrup
Heat juice and sugar in saucepan, stirring thoroughly until fully incorporated.
Allow to cool.
Step 3: Mix and Enjoy!
Gradually add 1-1/2 ounces of the cooled syrup to the glass. Why? There's something in the Splenda chemical makeup that causes the carbonation to flare up, and fizz-over is possible. It would take a scientist to explain it, and my wife isn't home as I write this. So, add gradually. Trust me.
Some Closing Notes
Yes, I know it's pink, and the commercial stuff is uh--not pink. I happened to have pink grapefruit in the house, courtesy of a food co-op of sorts called SHARE. Now I have a really neat use for them.
For my first batch, I ran out of Splenda and used half that and half actual sugar...probably closer to most of the SodaStream non-diet syrups.