Pour blood orange juice into ice cube trays to just below divider rims. Freeze until solid, at least 2 hours.
Meanwhile, in a 1 1/2- to 2-quart pan over high heat, stir 1 cup Melogold juice and sugar until mixture boils and sugar is dissolved, about 5 minutes. Let cool, then cover and chill, at least 2 hours. Or nest pan in ice water and stir often until cold, about 10 minutes.
5{en juice cubes from trays and divide cubes equally among glasses (about 2 cups each). Pour equal portions of Melogold juice and the chilled fruit juice syrup into each glass, then fill to rim with club soda. Garnish with blood orange slices.
Servings 0
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.