BWCA.com Gear Guide
Gear for the Boundary Waters, Quetico, and Canoe Camping Locations
Platypus CleanStream Gravity Filter System
Filtering water has never been so easy-let gravity do all the work with the pump-free Platypus CleanStream gravity filter system. System includes 2 four-liter reservoirs, 1 for unfiltered water and 1 for filtered water; reservoirs have hang loops for eas
Reviews for Platypus CleanStream Gravity Filter System
I normally paddle with a Katydyn Hiker Pro, and it has served me well for many years. This year, however, going in with a group of five, I decided to try this system. Its reported speed was what intrigued me most--four liters in about two minutes--far less than what it would take to pump the Hiker Pro.
From the first use, I was a convert. It provides fast and convenient access to water, especially while in camp where it can be hung from a tree. From reading other reviews of the product (on this site, and others), I was a little concerned about potential clogs and the backflushing process. It turned out to be a non-issue once I got used to using the system.
Another reviewer recommended a pre-filtering system. While by no means necessary, I can understand the benefit of removing any larger particles from the water before filtering it. You could sieve the water through a clean bandanna, if desired. I generally found it easier to simply be picky about fill locations--not in locations where there is a lot of obvious material on the surface, nor in places where your feet may have stirred up sediment from the bottom.
The placement of the line on the dirty bladder was well designed. It sits not at the bottom end of the bladder, but slightly above it. This allows sediment and debris to settle all the way to the bottom of the bladder, reducing the amount of material that will pass through to the filter.
BEST PRACTICE #1: When possible, work to fill a ways out from shore, and by dipping the bag well below the surface. Getting it below the surface can be tricky at first, because of the air in the bag, but you can get it done with practice.
BEST PRACTICE #2: Gather the water using a collapsible bucket (out from shore and below the surface), and use it to fill the dirty reservoir. If the bucket's capacity is larger than the dirty bladder, you have spare water ready for your next fill (or two!). This was our preferred method.
The backflushing process is straightforward: simply raise the clean bladder higher than the dirty bladder until sediment is cleared. Typically backflushing starts with a stream of air bubbles. Once the bubbles clear, you may see a cloud of sediment/particles begin to appear in the dirty bladder. Allow the water to flow into the dirty bladder for 10-15 seconds (after the air bubbles are gone) and you should be ready to filter again. We found that backflushing regularly kept the flow rates fast. Backflush anytime the system is rigged correctly (dirty bag above the clean one) and seems to be going very slowly.
BEST PRACTICE #3: Leave some water in the clean bladder at the end of the day. After sitting overnight, we found that flows were often a bit slower in the morning. By leaving a bit of water (as little as a couple of inches) in the clean bladder, you have water available to backflush the filter to get things going again in the morning.
The only improvement I would like to see with this product, would be the addition of a quick-release connection on the line between the filter and the clean bladder. I'm going to add one before my next trip. Disconnecting from the filter by pulling off the clean line just seems that it will eventually loosen/weaken that connection.
BEST PRACTICE #4: Before you disconnect the clean line (so as to use your clean water), adjust the quick-connect elbow attached to the dirty bladder so that it is pointing up (toward the top of the bag). Once the clean line is detached, let the filter hang down. The weight of the filter will cause the line on the elbow (at the dirty bladder) to kink closed, preventing you from losing filtered water which otherwise would continue to flow (assuming the dirty bladder has some water in it) through the filter.
The bags are pretty sturdy. The dirty bag has a very heavy duty zipper bag opening, and it has metal grommets where its hang lines/handles are attached (likely due to their location at the ends of the zip-closure). The clean bladder simply has holes in the bag edge, but no grommets. At first I was concerned that the weight of the water would cause those attachment points to fail, but my concerns proved unfounded.
BEST PRACTICE #5: If hanging the bladders from a tree, make sure there are no sharp points (e.g., broken branches) where the bags will hang.
BUILD-YOUR OWN OPTION: Since replacement filters and silicone tubing are available at retail and online, it should be possible to make your own gravity filter system using bladders, buckets, bags, or any other means of holding water. I'm presently thinking about doing just that for a much higher capacity system
OVERALL: This is a fantastic system for anyone who wants to spend less time pumping and filtering, and more time enjoying the wild around them.