01 - Combine cold water, lemon juice, and maple syrup in a large pitcher. Stir thoroughly until the syrup dissolves completely.
02 - Whisk blue spirulina powder with room temperature water in a small bowl until fully dissolved and smooth.
03 - Pour the spirulina mixture into the lemonade base. Stir until the color distributes evenly throughout the pitcher.
04 - Taste the lemonade and modify sweetness or acidity by adding more syrup or lemon juice as preferred.
05 - Place ice cubes, lemon slices, and fresh mint leaves into the pitcher or individual glasses. Serve immediately while chilled.