Glenn, I thought I would give you a little more info on the Hyperflow. I intended on writing up a detailed report on it after I use it again, but I probably won’t get out until August. So, based on one 7 day trip where I used it about 2/3 of the trip I’ll give you my observations.

First off, I use Platypus containers and a soda bottle. This is an important detail because the Hyperflow output fitting “press fits” into the opening of these containers. So basically I can push the filter output fitting into the container opening, and the container just “hangs” there while I am pumping. Surprisingly, the fit is quite snug, which is really nice because I haven’t yet had a container fall off while filling it.

On to my general observations. As indicated in my earlier post, this filter is light (8.64 oz on my scale for everything except the wide mouthed bottle adaptor), small and outputs a lot of water on each pump. I have found that the pumping action on it takes a little practice, and does require some force. If one were to pump 4 – 6 liters at one time like I typically do, this thing will wear you out. Whipping it out just to do a liter during a break is pretty nice though. The other thing about the pumping action that is a little annoying is that the part of the filter where the output fitting goes into the container is also within close proximity to one of the hand holds for pumping. This makes it pretty hard not to touch the container opening with ones hands while pumping. Not a big deal, but I wouldn’t want to do any filtering with really dirty hands. I have also noticed that the pre-filter is a little finicky, and it is sometimes challenging to get it to sit in the correct orientation in the water.

The back flush has gotten a lot of bad press. When I initially bought the filter I thought that doing a back flush every 8 liters would be the deal breaker just because of the extra work. It really hasn’t been that bad, and frankly being able to field maintain the filter is a nice option since other filters (like my Katadyn Hiker) are toast once they get backed up. The back flush, when it works properly, only takes a couple of minutes. I created a setup where I attached some cords to one of my 1 liter platy Hosers. I just hang the Hoser upside down on a branch, pull the mouthpiece off of the drinking tube, and push that right onto the smaller nipple fitting on the output of the Hyperflow. Then I just pump it 10 times and I’m done.

My main complaint at this point in time is that I have had the airlock problem while trying to back flush. What is weird though is that during the trip I was able to get the back flush to work after a few separate attempts, and then it worked every time after that. Basically what was happening with my filter is that the smaller red check valve (there are 2 that have to be reversed to do the back flush) was somehow getting a “suction” created on it. Once this happened the only way to break the suction was to open up the filter and pull the valve out thus removing the suction. I don’t know if it was just a “break in period” thing or what, but the smaller check valve finally loosened up a little where it would let the water through on the back flush without the suction being created.

So what are my thoughts...I think like the Hyperflow. I still need to get out again with it on a trip where the back flush actually works properly, and then I may really like it.