In a medium bowl, combine the almond flour, chopped pecans, and sugar free powdered sweetener and stir to blend.

Pour in the cooled melted butter and mix until the crust mixture is evenly moistened and resembles damp sand.

Press the mixture firmly into the bottom and up the sides of a 9 inch pie dish, using your fingers or the bottom of a measuring cup to create an even crust. Refrigerate while you prepare the filling.

In a large heat safe bowl, pour in the boiling water. Sprinkle the sugar free lime agar-agar powder over the water and stir until the agar-agar powder is completely dissolved and no crystals remain.

Add the ice water to the agar-agar powder mixture and stir until the ice has fully melted and the mixture cools slightly.

Add the whipped topping to the cooled agar-agar powder mixture and gently fold until mostly combined, then switch to a whisk and whisk until the filling is smooth, uniform in color, and lightly thickened.

Refrigerate the filling for 20 to 30 minutes, until it thickens to a loose mousse consistency that is still spoonable.

Remove the crust from the refrigerator and spoon the thickened filling into the crust, smoothing the top with a spatula.

Sprinkle the lime zest evenly over the surface of the pie.

Refrigerate the pie for at least 3 1/2 hours, or until fully set and firm enough to slice cleanly. Slice and serve chilled.