1. In a large bowl, mix together grapefruit, lime, simple syrup, tequila, and club soda.
2. Fill the popsicle molds 1⁄3 full with the mixture and put in the freezer to freeze.
3. Once frozen, take out and add the orange juice and freeze again.
4. Lastly, once frozen, add the rest of the grapefruit liquid and freeze one last time for at least 8 hours.
5. Serve with a mixture of salt and lime zest.
TIP: Because alcohol does not freeze, some of these pops will not get completely frozen. They’ll all freeze a bit different; the more alcohol in them, the less hard they’ll be. Turn your freezer up high and you’ll be fine!