Talking to an old friend this evening. Talked about camping. I never heard of this.......If you take a container of water that is cloudy or not exactly clear......Take a small amount of alum like a quarter teaspoon and toss it in the water.....stir it around until it forms a glob and remove it...your water will be clear as the alum has removed the solids causing the cloudiness. Run the H20 threw the water sterilization unit of your choice and you'll some pretty good drinking water. Anyone else hear of this method?