This is my second attempt on a lime soda and in soda making and it turned out pretty good, so here's the recipe:
4.5 gals water
1 gal corn syrup
1lb malt dextrin powder
fresh juice from a dozen limes
fresh zest from a dozen limes
Boil water + syrup + dextrin for 20min, add juice and zest on last 5min. Zest in a muslin bag.
Cooled to 80F, in a keg and into fridge. Carbodate at 60psi for couple of days. Dispensed at 15psi.