Rinse all of the fruit well. Remove the rind from all the fruit; reserve 1/4 grapefruit rind, 1/2 the rind of 1 orange, and all the lemon and lime rind. Thinly slice reserved rind; discard remainder. Chop all the fruit. Place fruit, their juices and rind in a large pot. Add water and refrigerate overnight. Over high heat, bring to a boil; reduce heat to medium and cook 20 minutes. Remove from heat and let stand 1 hour. Stir in sugar; set aside until sugar dissolves. Add apple juice and Sweet ‘N Low. Over medium heat, cook, stirring frequently, 1 hour or until very thick. Spoon into hot sterilized jars, allowing 1/4-inch headspace (or follow manufacturer’s instructions if different.) Wipe rims with clean cloth dipped in hot water. Close according to jar manufacturer’s instructions and process in boiling-water bath 10 minutes.