In a large stock pot combine water, Gentle Sweet, and salt. Bring the mixture to a boil over medium high heat. In a 4 cup measuring cup combine 2 cups cold water and 2 cups Clear Jel. When the contents of the stockpots comes to a boil, slowly pour in the Clear Jel/water mixture, whisking continuously. Reduce heat and cook until the filling is clear. Remove filling from heat. Stir in fresh or frozen blueberries and lemon juice. Fill jars with filling to the neck of the jar. Wipe the top of the jar rim clean with a cloth. Add lids and rings. Place jars into a prepared Waterbath canner. Water should be at least 1 inch over the top of the jars. Bring water to a boil. Simmer gently for 30 minutes. Remove jar from canner and allow to cool for 24 hours. Check seal. Remove rings. Wash jars and store in a cool place. 11 pints