-- Last Updated: Feb-24-13 7:30 PM EST --
On two different Yukon 1000 canoe races, we used the PurReliance chemical system to both de-silt and purify our drinking water. Did not need to filter. It worked well for us. A 6-man voyageur canoe needs lots of water to paddle 1000 miles. We purified 5 gallons at a time. Two small packets does it. I carried alum as a backup, but didn't use it.
http://www.relianceproducts.com/products/purification-emergency/220.html