GravityWorks 4.0 L Filter System

Realize this is a paddling forum and so water abundance is not such an issue for filtering but thought I would add my comments on the 2 Liter system which I just used on a 6 day backpacking trip.

Pros have been covered by folks above already -

Con - the 2 liter "dirty" bag can be tough to get enough water in to filter if the source is a very shallow intermittent stream or seep as some of ours were - in these situations you can only get about a half liter at a time - if that even - two MSR pumps we had did much better in this situation.

Having two different filters gives redundancy and options.

Really like the 2 L system though and will be buying the 4 L fill bag for use on paddling trips and car camping

The Pros:
- The gravity feed system allows for purification of several liters of water at a time without pumping. So, you can set up/breakdown camp while your water supply is replenished.
- The clean and dirty water bags, filter, etc. are all very clearly marked. In the dark, this is important!
- The quick-connect system lets you fill your hydration pack directly to avoid spilling and hassle. It also allows for some other cool things, like moving your clean water bag between hydration packs.
- It's light. While it doesn't pack down super-tiny like some systems that do a smaller amount of water at a time, it's still very lightweight.
- Filters are long-lasting and not too pricey.

The Cons:
- The only con, really, is that it is a bit bulky no matter how you pack it. I can't think of a way the manufacturer could change this, but it an get in the way if you're using it for backpacking or kayaking and are working with limited space. I've not found this prohibitive enough to make me want another system, but it's worth noting so you can leave space in your gear packing.

This is the fastest system for filtering water, particularly large quantities, is one of the lightest filter systems, and requires little to no maintenance. I probably got about 1500 liters out of a single filter. It is an extremely versatile system since you can filter a small amount or a large amount of water at a time which works well for a camp of multiple people, or for a line kayaker.

The primary drawback to this system is that is more expensive than the average pump filters, but its ease of use make it worth it for me.

Pros: it's fast, easy to use and easy to maintain.
Cons: It's expensive and difficult to use with small, non-flowing water sources (which shouldn't be problem for kayakers). The Platypus waterworks runs about $120 and a replacement filter is about $40.
The cost is the only reason I gave it a 9 instead of a 10.