The Allrecipes nutrition calculator doesn't factor in net carbs, so the amount of carbs listed appears higher than what is really in the bars. I used Swerve(R) as the sweetener here, and while it does contain 3 to 4 g of carbs per teaspoon, the ingredients in Swerve do not affect blood sugar, so the carbs it contains are considered non-impact. Because of this, a common practice is to subtract fiber and sugar alcohols from the carb total, making it zero carb. I have calculated the correct carbs for this recipe as 5.1g per serving, not 17.8g.
You can use granular sweetener in the filling mixture, though I prefer the powdered version since it dissolves better. You can pulse granular sweetener in a blender or food processor to achieve a powdered consistency. For a sweeter bar, add an additional 1/4 cup of sweetener to the filling mixture.
For 1 cup of lime juice, you will need approximately 8 limes.