Hydration Tube Inline Hijinks

Not actually Erin.

Picture by KJ Photography

& is used with permission.

If you have a hydration bladder in a backpack, you know how difficult it is to refill without unpacking the entire thing -- which is not something you want to do on a hike, let alone while bugging out on foot or trying to get home.

If you're refilling in the wild, then water purity is also a concern. Sure, you could boil water and then pour it into your bladder after it's cooled, but that requires you to make camp and build a fire. If you have a long ways to go, or don't have the time or ability to make a fire, that might not be a good choice.

I'm going to show you how you can refill your hydration bladder using its drinking tube while filtering it at the same time. I consider that last part very important, because once you introduce dirty water to your system it must be considered permanently dirty until you're able to clean it with soap and hot water, and during an emergency you might just forget that your formerly clean water supply is now dirty. With my method, everything that goes into your hydration bladder will be clean.

What You Will Need

1. Mazama MagmaFlow Quick Disconnect Coupler
2. Two Sawyer Products SP115 Fast Fill Adapters for Hydration Packs
• Some pumps (below) may come with fast fill adapters. What's important is that you have two sets of male & female adapters. 
3. Sawyer Products SP110 Inline Hydration Pack Adapter for Screw On Filters
4. Sawyer Mini Water filter. 
• If you do not already own a Sawyer Mini, then purchase their Dual Threaded Water Filtration System which comes with the screw-on adapters in #3. This will save you $4.50.
5. Superglue, epoxy putty, or plasti-dip. 
6. A pump filter. 

About That Pump...

This will be the most expensive part of the setup, but it is necessary to fill your bladder via the tube and, in my opinion, the convenience is worth the cost. I'm using a Katadyn Hiker which I bought about 10 years ago when I first started getting into prepping. It is also a filtration system, and the fact that this means I'm double-filtering my water is a feature in my book. 

However, the quality of filtration is less important than having a pump. If you can find an inexpensive pump that doesn't need a filter to operate, go ahead and use that so long as you feel its construction is durable enough for your needs. I couldn't find any like that, and most of the hiking pumps to be found online are about $50... although I did find one on Amazon for about $27.50 with no reviews whatsoever. I consider that to be super sketchy, but am including it here for sake of completeness. 

Instructions
1) Cut your drinking tube approximately one inch from where it attaches to the mouthpiece and attach the MagmaFlow coupler. Be sure to pair the larger part of the coupler with the longer part of the tube! This is important because the large piece has a shutoff valve which will prevent water from leaking out of your drinking tube when you take off the mouthpiece. 

2) Take your Sawyer Mini and attach the gray threaded adapter to the bottom. Then, using the tubing and fast fill adapters, place them like so:

You may find it useful to remove the cap from the drinking end of the filter like I did.

If you are using the Dual Threaded Sawyer, then you will unscrew the pop-up valve on the drinking end and replace it with the blue adapter.

https://amzn.to/2JMKeFZ

3) Take the remaining fast fill adapter and seal the ends with something tough and waterproof, like plasti-dip or epoxy putty. Even superglue will work, although I recommend you color it in so that you can tell at a glance which of the adapters are sealed.

4) Your finished product will look like this. The sealed caps will prevent contamination of the clean output end by droplets from the dirty input end. This is how I store it in my GHB.

Operation
To refill your hydration bladder with inline filtering, do the following:

1. Remove bite valve from drinking hose using the MagmaFlow disconnect. 
2. Remove sealed valve from the clean end of the Sawyer filter and place it over the bite valve lead to keep it clean.
   
   
3. Insert clean end into drinking hose. 
4. Remove cap from dirty end and place it where you won't lose it. 
5. Assemble your pump and plug its output into the dirty end of the Sawyer. 
6. Place input of pump into water and begin pumping. 

The finished version will look something like this:

Performance

It is reasonable to expect that this double-filtration setup would increase the time it takes to refill a hydration system, but that is not my experience. I tested this with a 2 liter bladder and 2 liters of water. 

• Without the Sawyer, it took me a little over 2 minutes to fill the bladder with 2 liters of water. 
• With the Sawyer, it took me about 1 minute 50 seconds. Since adding another filter cannot make the pump go faster, I attribute this increase to warming up the pump and/or increased familiarity with the process. 

Be Advised!

With your hydration bladder inside your backpack it will be difficult to see how full it is! Be careful not to over-fill it or else you risk rupturing your bladder. 

To prevent over-filling, I recommend that you practice with a known quantity of water. For example, it takes me 60 pumps to move 1 liter of water; therefore, if my hydration bladder is empty then I know I need to pump 120 times to fill it. 

Once you have this number, write it on your pump with a permanent marker. 

Final Thoughts

I am not familiar with all pump systems, but the Katadyn Hiker has an expensive filter ($40) with a limited lifespan (200 gallons) and no ability to backflush it. Conversely, the Sawyer Mini can be backflushed and can filter up to 100,000 gallons over its lifespan. 

With that in mind, if you expect to be drinking from a lot of dirty sources during a bug out or get home scenario, it might be prudent to use the cleanable filter with the longer lifespan to handle the majority of the work. In that case, the solution is simple: get another set of fast fill valves and place them in the input hose of the pump, so that the pump filter is only processing already filtered water. 

Only you know which version is right for you.