In a jar with a tight-fitting lid combine chia seeds and 2 cups water. Refrigerate for at least 8 hours or overnight.
Place tea bags in a 2-cup glass measuring cup and pour 2 cups boiling water over them. Let steep 5 minutes, then discard tea bags.
In a medium saucepan combine raspberries and ¼ cup water, bring to a boil and cook, stirring occasionally, until raspberries are completely broken down. Transfer to a fine mesh sieve set over a bowl and use a silicone spatula to press all the juice from the berries. Discard the seeds.
Stir the raspberry juice into the hibiscus tea. In a pitcher stir to combine chia mixture with tea, stevia, and lemon juice. Refrigerate to chill completely.