1. Place water, chicken, ginger, chilis, mushrooms, fish sauce, lemongrass, Splenda, and salt in a saucepan. 2. On high heat, allow the soup to come to a boil, and then lower to medium heat. Add in the coconut milk and stir. Let the soup simmer for 10-15 minutes. 3. Stir in lime zest, lime juice and fish sauce. 4. Serve with springs of cilantro and lime wedges.