Water: Sawyer Mini + Gravity Filter Mods

Status: 100% in the bag!

Weight: Filter--56 g (wet), Dirty water bag--42 g, NEW water scooper--18 g  8 g, Backflushing tool--36 g, Backup chemical treatment--6 g

Mods: 2 grams of cord/cord locks to make it a gravity system, New ziplock water scooper

Alternatives: I like the filter, but many people use Aqua Mira or other chemical treatment to save a bit of weight. I'm not 100% certain that this is the water scooper I will use, but it worked ok. New water scooper! See below...

In the last post, there was a picture of my planned setup for water treatment. Here's the system in more detail.

From the top, the system consists of a cord loop and cord lock attached to the dirty water bag via two tiny holes I cut near the bottom of the bag. The filter screws onto the dirty bag, and a spout goes to the clean water bottle. 

The loop on the dirty bag is about 4 feet of cord and a mini cord lock (both from ZPacks). It's set up as a loop so I can put it around a branch or small tree. When I pack the bag and filter, this loop also helps hold everything rolled up tightly.

This little loop is the part I really like. There's no way to screw the clean end of the filter to a water bottle, so this little loop of cord keeps them together.

It's long enough so the cord can slip around both the neck of the filter and the neck of the water bottle. I just move the cord lock down toward the bottle when they're attached to hold everything together. The flow rate isn't super fast, so if you don't want to wait, you can still squeeze the dirty water pouch to speed things along. Having it hung like this means that you don't have to bend over or balance everything together to make it all work. Just hang and squeeze!

You can put a few twists in the cord to tighten them together so the cord doesn't slip off the filter. If your cord is short enough, this doesn't matter, but it can help tighten everything together.

This little cord does, of course, put some stress on the bottom spout of the filter, but the thing seems to be really well attached. I'll monitor it to be sure the weight doesn't damage the filter long-term. I can also hang this low so the bottle (and the water weight in the bottle as it fills) is resting on the ground. The cord lock on the dirty bag gives me about 10" of adjustability.

Weight of modifications? 2 grams. Worth it.

Some water sources are really shallow or slow-running, making it difficult to get water into the small opening on the dirty bag. I originally cut off the bottom of a small dirty bag to use as a scoop (above left). Pros: It's stiff, water flowed in easily even when the water source was only about an inch deep. Cons: Another spout makes it harder to roll up the dirty bags with the filter (minor gripe), it takes a little juggling to open the spout while not spilling it out the open end and getting it into the big dirty bag, and I think I can make something lighter.

I shouldn't have trouble with low water sources at the time of my hike due to snow melt and rain, so I've modified a ziplock bag to use as a scoop and pre-filter instead. The pre-filter is just a piece of cloth that will help keep bigger sediment/particles out of the main filter. Most people just use their bandana as a pre-filter, but I'm opting for this little swatch instead. If the water source is flowing well enough that I don't have to use a scoop, I can still use the pre-filter cloth just by holding it over the opening of the dirty bag with the little loop of cord from the main filter.

This ziplock has a little corner cut off for the water to flow out. The mini clip will keep that opening closed when I'm scooping water. It can also help keep the pre-filter in place. Then I just have to hold the ziplock over the dirty bag and undo the clip. If the ziplock wears out, it's dead simple to replace, and it's easier to roll up and store with the filter, too! Weight savings: 10 grams.

Not pictured: Backflushing syringe. The filter comes with a syringe for forcing particles back through the filter to keep it cleaner and keep water going through at a reasonable rate. If you don't do this, the filter can get clogged. The syringe helps keep the filter cleaner and the water flowing. You can see that part here. Some people don't carry it because it's kind of heavy (an ounce!), but it's what keeps the filter healthy. I've seen a couple of people make their own lighter versions, but I'm not sure they will work long-term, so I'm going with carrying the tool for now. [edit: Realized that I can also use the backflushing syringe to irrigate open wounds, so now that I have a second use for it, I'm happier with it in the pack.]

I'll also be carrying a few Katadyn Micropur Purification Tablets for backup water purification in case the filter stops working or in case I have to use some really funky water. They are simple and weigh very little, so they make for a good backup plan. I'll probably take enough for 2 days of water treatment just in case.

Note: "Just In Case" is a phrase you're supposed to look out for when trying to lighten your load. If you have a lot of "Just In Case" items, you're probably packing too much stuff, but in the case of water treatment, which is a pretty important part of hiking, the "Just In Case" is prudent.

Some people experienced problems with Sawyer's earlier bags leaking. The bags have been improved, and I'm pretty gentle with my gear, so I'm not taking a backup dirty bag. I will have two water bottles with me that are compatible with this filter (Smart Water bottles), so if this dirty bag gets destroyed, I'll just use one of those bottles as a dirty bottle. On a different trail with limited water, I'd take another bag, but I don't need the capacity on this trail.