As promised here's the method for making my 'red tonic', hibiscusbased drink that's great with or without carbonation from your SodaStream. Cheap, easy, and you stay in control of the sweetening. It might even be good for you!

For a 2L finished batch:
10 grams hibiscus
2 grams citric acid (optional)
Sweetening to taste (see video)
500 ml boiling water to steep
1.5 l water to finish (carbonated or not)
Other flavours (optional)