Begin by preparing the strawberry syrup. In a small saucepan set over medium heat, combine the water and sugar, and stir.
Heat until the sugar dissolves.
Once the sugar has dissolved, add the frozen strawberries to the saucepan.
Simmer the strawberries and sugar mixture on low heat until the strawberries become very soft and the syrup has thickened, about ten minutes.
Strain the syrup into a glass measuring cup, and discard the strawberries.
Allow the syrup to cool at room temperature for a few minutes, and then place it in the refrigerator to chill completely.
As the syrup cools, prepare the tea. Add the three tea bags to the 2 cups of boiling water, and allow the tea to steep for about 30 minutes.
Remove the tea bags and discard.
Chill the tea until ready to prepare the iced tea lemonade.
Fill a large pitcher with ice.
In a large bowl, stir together the strawberry syrup, the chilled tea, lemon juice, and seltzer. If you find the drink too sweet, add more seltzer water or regular water until the drink is sweet enough for your taste.
Pour the iced tea lemonade into the pitcher with ice. Add a few thin slices of lemon to the pitcher. Serve the iced tea lemonade over ice and garnish with strawberries and additional lemon slices.