So.... Which one is better, the Platty CleanStream or the MSR Autoflow Gravity Filter? I did notice the MSR version has a mesh screen "prefilter" (according to a reviewer) where as the Platypus CS does not. Sure would like to hear everyone's comments! Thanks!

Red Baron, I read where you have experienced the same bag closing problems that I have. I recently called Cascade Designs again regarding this issue. We both found that closing the bag against a hard surface worked successfully. CD added that by applying "Chap Stick" to the zip lock aided in closing. Apparently other folks have had this problem. Since it does work as long as you don't overfill the bag, it also makes it easier to open up! The Cleanstream is still a good system & makes filtering water a breeze.

I don't have experience with the MSR filter mentioned, but have used the Platypus filter for more than 2 years now and really like it. I never bother to close the "dirty" bag, since I just hang it up on a tree branch. It is difficult to close the clean bag, but as mentioned in other reviews, pressing it against a hard surface (like a tree trunk) or using both hands opposing each other and working it closed by pinching rather than sliding works. And if you hang the "clean" bag on a tree lower than the "dirty" bag, then you don't really need to close it either (or you can just have the water flow into another container or directly into drinking bottles if desired). After filtering, I detach the "dirty" bag + filter, hang it on the lower limb and hang the "clean" bag from the higher limb after closing off the valve. I haven't had the need for a pre-filter, so I'm not sure if that would be helpful or just clog up faster (my other backpacking filters with prefilters tended just to clog quickly and using a coffee filter over the intake was much a better solution to preserving the filter life). The platypus filter is easily back-flushed, by reversing the direction of the flow/bags, so I don't think clogging is really much of an issue. Personally, I find this filter a lot easier to use than a traditional hand-pump backpacking style filter. Not only that, but it filters a LOT of water in a very fast time. I really like the control valve on the clean hose, which allows it to be easily used to fill bottles (or mouths) directly from the clean back with no spills. It's really a super filter at a good price!

The "zip lock" closing problem I was having with my Cleanstream was a result of the following reasons: 1. The plastic @ the closure is a much heavier gauge than the rest of the bag. This being the case doesn't allow a simple "pinch & swipe" action as previously stated, to work effectively. We're not talking about a 0.5 mil thick baggie here. 2. The more water in the bag, like four liters, the less space there is to get a flatter closure area. 3. Cold water, which we will all be filtering, only makes the plastic closure more rigid. If we were filtering warm water, this would be a mute point. I now fill the water bag with four liters & with my thumbs, press the closure area against a hard surface, rock, tree, etc. & the "zip lock" closes very easily & completely. FYI, place a clean item under the bottom of the water bag if it touches the ground. This will prevent the hose/tube connector from getting dirty. Also, this was a brand new unit, right out of the box where age, material/UV degradation, wear & tear, etc. wasn't even an issue.

Phil, the material used on the Clearstream is different than past Platypus material. The Ziplock is much easier to use, but still takes effort to close. I would pinch, then swipe the ziplock to make sure it's closed. Not taking the time will mean that it won't seal properly. The other thing you should know is the Hyperflow has a Gravity Kit which transforms the Hyperflow into a gravity filter giving you almost the speed of the Clearstream or AutoFlow. It's easy to use by simply replacing the prefilter on the Hyperflow with the hose from the dirty water bag of the Hyperflow Gravity Kit (the bag is very similar to the AutoFlow). You next attach a bottle to the Hyperflow and extend it fully allowing the water to flow. You will get about 1.2 Liters per minute. The benefit to this set-up is you can have the Hyperflow for quick fill-ups and a gravity filter for more basecamp applications.

WallDiver- Thanks for getting me going on doing my research. I've learned to hide things with moving parts from my wife, but she's now taken to melting things in the dishwasher, and swiping headlamps for reading in bed while blazing through all my AAs. Jeff- Was the "zip-lock" problem a matter of wear and tear? No UV degradation or fatigue issues on the bladders or handles after a couple years? It also seems that air-lock is giving some people problems on the MSR. How's the Platy in that regard? What I'm trying to find is a compromise on having to also carry my HyperFlow, but instead of the gravity flow specifically for that, I would rather have a separate system. Can I get this set-up and flowing trailside fairly quickly?

Jeff, Phil, Thank you for your comments. The whole reason the need for a new way to filter water is because my significant other broke my Katadyn pump. (Last week she broke my watch... "it just broke") So, I figured I look at a gravity feed filter so there wouldn't be any moving parts to get broken. Anyway, I like that Platypus gives you another 4L reservoir to accomodate different options/planning (even if I'll leave it at home to carry less on occasion). The MSR Autoflow Gravity Filter's internal mesh filter, as Jeff states, is of minimal concern because you can just let the big stuff settle out. I do like the roll-top closure better on the MSR system over the zip lock of the Platy bags. Bottom line: if the MSR were $30 cheaper I opt to go with it, since it doesn't have the second clean water reservoir.

Both systems work great & are certainly time & work saving. I initially had a problem closing the "zip-lock" top on the Cleanstream until I tried closing it against a hard surface rather than using only my fingers. The Autoflow uses a roll-up, FasTex buckle closure. Both systems use the same filter cartridge, color being the only difference. Both have four liter capacity water bags/reservoirs. The Cleanstream includes a clean water bag/reservoir which can be eliminated to save weight, in this case working identically like the Autoflow. I don't know how effective the MSR screen prefilter is, but I do know that larger particulate matter doesn't make it to the Cleanstream filter cartridge. This is accomplished by allowing the unfiltered water to rest for ten minutes before filtering. The tube connector is located 1.5" up from the bottom of the "Dirty" water bag allowing any possible sediment to fall below this connection. You can read my contributions regarding the Platypus system below. I'm totally sold on anything Platypus. They are all high quality products & are backed by the great team of folks @ Cascade Designs. The choice is yours & either product would give you outstanding results!

I've been wrestling with this choice myself. Seems to me that the basic function of the systems are the same, the filter cartridges are the same and have the same lifespan, and the pre-filter on the MSR could come in handy. Also, Jeff Gerhard mentioned that he ended up basically ditching the second bag, and has recently been having problems with the "zipper" on the Platy engaging properly, whereas the AutoFlow's top rolls over. At this point, I can't base anything on experience, but being in same boat, I know what direction I'm leaning in.