In a small bowl, whisk together calcium lactate and the 1000 grams (1 Liter) of water until fully dissolved. Let it rest for 4 hours (or overnight)
Bring water to a boil and add tea leaves. Steep for 5 minutes, then strain and let cool.
In a blender, combine cooled tea, sugar, milk, and 120 grams of ice. Blend until smooth.
In another small bowl, whisk together sodium alginate and the fruit juice until fully dissolved. Optionally: add food colouring and stir until smooth.
Using a pipet or a syringe, or Spherification Bottle, drop small droplets of the alginate mixture into the calcium lactate solution. Let the droplets sit in the solution for 2-3 minutes.
Remove the 'pearls' from the solution with a slotted spoon and rinse them in a bowl of fresh water.
Add the alginate pearls to the bottom of a glass, then pour in the tea mixture. Serve with a thick straw.