You can dress this up with some ice cubes and bitters (available from a liquor outlet) for a lovely evening drink, and/or some mint, borage flowers or citrus slices for decoration.
You can use any mix of citrus: rangpur lime, lemon and limes, grapefruit and blood oranges, or plain lemons. All are great but anything works.
2 cups zest & citrus juice
of your choice 4 cups sugar 2 tbsp epsom salts 1 tbsp citric acid 1 tbsp tartaric acid 500ml boiling water 1.5l cold water
Dissolve the sugar, epsom salts, citric acid and tartaric acid in the boiling water.
Add 1.5 litres cold water*, citrus juice and zest. Dilute to taste, usually about a quarter to a third with water or carbonated water (I use a soda stream).