In a small pot over medium high heat bring the flavored soda water and agar agar powder to a boil. Once it boils add the sugar, stir and return to a boil.
When the sugar has come to a boil pour it into the prepared pans.
Drop a little food coloring on top of the jelly and swirl it in with toothpicks, you can stir it all in or leave some clear spots and swirled colors.
Put the jelly in the fridge for at least 2 hours or until firm.
Line to sheet trays with parchment paper, turn out the jelly and break it into shards or you can cut it into gem like pieces. Place the jelly pieces on the trays leaving plenty of space between so the air can circulate and dry them out.
Leave the jellies to dry at room temperature for 3-5 days turning them over at least once, they should be completely dry, no stick or tacky spots and they outside layer should be hard.