[15 of 18 customers found this review helpful]

MSR HyperFlow Microfilter Review

Works for about a day

Super Informative

"I just got done hiking the Appalachian Trail, and carried the Hyperflow from Troutdale, Virginia to Maine. (about 1700 miles) I hated every minute I had to use this awful pump. I was replacing an older MSR miniworks, which was twice the weight and moved a very low volume of water. Because of the way I had my water system set up with a camelbak inside my pack that is very difficult to remove on a regular basis, I needed some sort of pump to pump water in through the drink tube.The technology behind this filter is flawed. Simply stated, backflushing does almost nothing to clear this filter once it gets clogged. So you basically have a very effective, as-advertised 3LPM pump that is even exciting to use, until it clogs for the first time. That first time for me was about 8 Liters. After that, it was the biggest pain in the butt to use this thing. The pumping became so hard that I would need to brace one arm against my knee to get the needed leverage. It was like a daily workout, and I dredded pumping water so much that I ended up skipping water sources and at times running out of water all together.No amount of "backflushing" would restore this thing to its advertised functionality. In fact, once the filter gets too clogged, the backflushing method does not work at all because you are basically relying on a vacuum to pull the water through the filter during a backflush, and that simply is not enough psi to do the job. (the same pressure that I needed to brace one arm against my knee to pump water through is required to pull water back out during a backflush via a vacuum). So, in the end the thing just gets worse and worse. I finally called MSR, and the freely offered to send out a new cartridge. This to me is evidence that they freely admit the problem. My new cartridge? Lasted for 5 Liters, and immediately was worse than my old one ever was.I knew dozens of hikers on the AT who had bought this thing, and NO ONE was still carrying it by the end. In other words, I was the only sucker. One hiker I knew who was carrying this piece of junk basically had MSR send a new cartridge to every town along the trail, before finally demanding a replacement Miniworks. Each [$]cartridge will last you a day tops before it needs replacing.I guess the upside to all of this is that you have yourself a great filter as long as you have the luxury of receiving a package from MSR every few days. If you do not have that luxury, then stay away from this product, which I believe is probably the worst filter ever made."