MSR  Guardian Gravity Purifier

This is a well built, easy to use water purification system. The operation is simple fill and hang the bag full of water. Open the clamp and let gravity work. I don't think backpacking was the intent for this filter, but works well for groups if you don't mind the weight. I think this would best be suited for international travelers or emergency preparedness situations. The flow rate was good, and the water comes out clear and tasteless. The only issue I could foresee is the dirty water bag can hold up to 10 liters of water. It takes a fair amount of strength to hoist a full bag and clip it to the holding strap. During use on the trail I had to prop to filter and hose on a trekking pole to get the flow rate up. All the parts are well designed, and worked as advertised. I really enjoyed the bottle connect system, which I added a quick disconnect to hook up to a water bladder. The cap has a graduated lid which connects to nalgene type bottles, platypus soft bags, and 20 oz water bottles. Overall a great system which will stay in rotation in my gear closet.

I used it when I went backpacking with some friends. At first I thought the 10 lt reservoir bag will be too big for the 4 of us ( plus 2 dogs) . To my surprise, we actually went thru the whole thing on the first night! It filtered water pretty fast and worked great with our 1 lt nalgene bottle but it didn't work as well with 0,5 lt bottle. We had to prop it up and it popped out occasionally . The system packed pretty small and it came with a small bag . Make sure to follow the instruction to store it properly .

As an engineer, I can really appreciate this product and all the work that went into developing it! It strikes a great balance between effectiveness and practicality. The 10 liter bag gives an ample supply of water, and the directions are super-easy to follow. All the parts are all labeled as well, for ease of use. The flowrate is great for a gravity filter and the end product has no residual taste issues, which is important for treated water. The gear all packs down small into a nice pouch, which makes packing it easier, as the tubes would get tangled easily otherwise. Cleaning was easy too as no backwashing was needed. I would definitely recommend this.

Typical, when I'm backpacking I use a light weight squeeze filter, which works well especially for its weight. However, I end up breaking at least one of the squeeze bags per trip and I find it a waste. This gravity filter helps fix that. While it's slightly bigger and heavier it's still small enough to carry for a group of two or more people. The large bag means that I also don't need to carry a Dromedary bag either to store water at the campsite. The filter is easy to use and has the added bonus of filtering viruses so I can bring it on international trips and not have to buy bottled water. Overall this filter is a welcome addition to my kit.

I use the filter on my trip last weekend for the first time. It was for seven dudes on a mountain bike trip at base camp. It performed very well. I thought that the flow rate would be a little bit higher. I would say that it’s a little bit less than half a liter per minute. But honestly since it’s a passive system, you turn your back and look over and see your water bottle is full and start telling somebody else to bring theirs over. I wish that the two adjoining clips at the top of the bag or a little bit larger because it’s hard to get them into the hanger carabiner . But the same time I think that I will connect those ahead of time next time and then just use the regular webbing clip to attach to a High Point instead of using two circle clips while trying to hold up 20 pounds of water. Other than that it’s pretty straightforward and I would recommend it for base Camp situation‘s with 2 to 10 people

I've used lots of pump style filters over the years and the Sawyer squeeze, etc. This purifier/filter is hands down the best one I have ever used or owned. The gravity set up is great and easy to use. The fact that it is a purifier is a huge peace of mind and a big advantage over any other filter out there bc none of the others are purifiers. I used this on a 10 day trip paddling the Grand Canyon. NPS regulations require everyone to urinate in the river and as you get lower downstream and outside the park, open grazing with cattle is present and the water just gets pretty gross by the last few miles as you enter lake mead. I purified water with the guardian that I otherwise would have refused to even drink and it turned gross brown water into crystal clear, clean water. Tons of silt the entire trip yet this purified did it's job without fail. I couldn't imagine buying another water purifier for my backcountry adventures with questionable water quality. I am a huge fan of this purifier!

The bag leaked out of the box and MSR never contacted me back despite repeated attempts at getting it fixed. I also felt like the flow rate was too low and the bag had to be hung really high with the target container really low to get water really flowing. I’m guessing this is due to it being a purifier as opposed to a filter. It would be nice to not have to use a pump as with the Guardian pump version, but I didn’t like how this worked. Coupled with the fact that they wouldn’t return calls I wound up returning it.

I really like this filter. I've been pumping my water for years, and after seeing other people's gravity filter systems, I was excited to try this. Everything about this is pretty intuitive: dirty water goes in the bag, clean, fresh-tasting water comes out the other side. I like the simplicity of the purge system and the universal water bottle adaptor. Don't expect a fast flow rate. That's a fair trade off for me as opposed to squatting by a river to pump. It's not the smallest and lightest filtration system out there, so if I were traveling light I'd stick with my water pump--but if you're in a group situation where you're sharing the load, or where weight isn't a factor, this would be a great resource, especially since the bag holds up to 10 liters. It comes with a nice bag--very much like one of those skinny packing cubes that hold 5 pairs of socks. It's nice to know that the filter excludes viruses and has been tested by the military in situations I'll probably never find myself in.

Got this to use for multi-day backcountry use. Just spent three days in the Manistee River Valley (Michigan) using this system. We ran about 30 liters of clear river water through this. The bag and hose assembly did not leak, the flushing system was incredibly easy and worked well (about 1/2 liter for each 10 liter fill), and the water tasted clean and fresh. The bag is super lightweight, but also strong and easy to fill - we hung it off a branch about 6' off the ground, just so the filter hung down about 6" off the ground. The flow rate was consistent, and filled a two liter pot in 2-3 minutes (temp at 50 F). The hose clamps and tube end cover are easy to use. This system was much easier to use then our sawyer squeeze for base camp (will still continue to use sawyer on trail). Given current state of health concerns, and that more people are involved in wilderness activities, we went with this filter for it's ability to remove viruses as well. We are glad we did, and I don't think we will ever need anything else. Ease of use and capability make this system well worth it's price for us.

Very intuitive to use, although the top doesn't seal very well (which means it works best if it is hanging somewhere very high up and not moving at all). Flow is decently fast (like a pot of boiling water, it goes faster when you aren't watching it). Needs to be hung pretty high up though, which can be hard if you are vertically challenged.