There is a nice article on the effectiveness of chlorine dioxide treatments against biofilms by Dr. Ryan Jordan. Yeah, that Ryan Jordan. He tests Aqua Mira, which is the same chemical as the Micropur tablets.

http://www.aquamira.com/bpl_2_efficacy-of-water.pdf

For water with more sediment or other gunk, double or quadruple the dosage. This is also a good way to get a sterile wash for first aid.

I've taken four crews since they started using the MicroPur at Philmont in 2005 and have always been happy with the ease of use. My 2012 crew fell in love with the Platypus gravity filter and decided to take it along (and their vote outguns mine, LOL), using it whenever possible, but there were still instances where the MicroPur was very handy (and we all carried a sleeve on us). We had twice as many dry camps as the trek was rated for, due to low water in intermittent steams and lakes at some of our trail camps (mid-July). We did a lot more water management than my crews have had to do on any prior treks in the past 17 years, due to a combination of the trek selected and the water availability. That said, we came prepared to be able to carry 5-6 liters each on our days on Phillips or Tooth Ridge, and we never ran dry.

Like many others have posted, leave the filter behind. Pack lightly. Don't take a Steri-pen. AquaMira tablets are handed out at every commissary and they are generous and light weight.

Every staffed camp has water. You will either pass through or stay in one just about every day on about every trek. As others have posted, ranger staff will post if water needs to be treated. A happy backcountry staff is a staff that has fresh water and doesn't have to treat their water every day!

Water availability is posted in Base Camp at Logistics. You will go to Logistics your first day in base camp. Go again in the morning you depart with your Crew Leader and note what is posted where and PLAN where you will get water if water is not available as posted. "Ample" does not mean free-flowing or clear!

We went this year (2012) arriving in base camp June 10, which is only 2 days from the opening of the ranch. The water boards were not all updated, since backcountry staff and rangers had not been everywhere or reported in yet. So we had two sites with little or no water. Had we absolutely needed to, we would have used a bandana to filter the scum out of the cattle pond and treated with AquaMira, but we managed through it.

Our crew had a few members with only 3L water capacity, and they wished they had more - not to keep full and carry all the time, but to fill in preparation for long and/or dry days. I recommend 5L capacity for everyone, and then plan when in your trek you actually need to carry the extra weight. This will change based on water availability throughout the season. Take extra collapsible water bags or canteens and use them on your dry days to supplement individual water storage. We carried two 3L canteens.

In camp, your water usage will depend greatly on how you plan to cook and clean. If you cook and clean the Philmont way (family style in a big pot that you then have to wash), you will need lots more water than if you cook in a turkey bag in the big pot (requires no cleaning if the bag stays intact) or rehydrate in the meal pouches. My 12-man crew brought 2 2L pots and other than for coffee or cocoa only heated 4L of water for meals we cooked in the bags. We ate out of food bags and ziploc bags. We also did no dishes as we had a human sump with us (ha!).

We had an early July trek and at the advisors meeting turkey bags were almost prohibited. Nothing much was said on individual hydration (mugs and bowls). The rangers will still teach the one-pot method as that's "policy".

We made sure that everyone had at least 3 liter capacity and among the crew had 6 additional 4 quart water bags. This got us through our Tooth side-hike with a little to spare.

Our crew leader also took pictures of the water board while in Logistics. This has helped a bit on the trail in the past.

Edited by dzierzak on 10/08/2012 06:39:07 MDT.

I love the GW, although I have the previous model. There are three caveats, though, some of which have probably been covered here.
First, *only* use clear-ish water. You can prefilter through a bandanna if you need to, which will at least remove the chunky stuff.
Second, *always* backflush. This is beyond simple...just lift the clean bag above the dirty, let it flow for a few seconds, and then clamp off.
And third, the ziploc-type seal on the dirty bag has always been a royal pain to close. We were hoping to use it as a (dirty) water carrier on dry camp days, but had to abandon that plan. I've heard other people complain about this, but I don't know if it's been corrected on the latest version (anybody?).

Liz in Seattle
2011, 2013

Unless folks really object to the taste of chlorine dioxide at Philmont, the pills work fine and do not fail.

That being said, I love my Gravity Works but it does weigh more than chlorine dioxide pills, and it can fail. I had to replace a filter after taking water three times from a very small, warm pond at 9500 feet in the Sierra Nevada earlier this summer. I suspect that what Ryan Jordan would call biofilms clogged the little hollow tubes. No amount of back flushing would clear the filter. So I replaced the filter.

As to the zip lock on the dirty bag, seems to work fine on my 2012 model.

Edited by btolley on 10/12/2012 09:23:03 MDT.

I only used one Gatorade pack a day at Philmont (if that), and drank treated water the rest of the trek and never noticed a taste or aftertaste from the chlorine dioxide tabs. But I rarely had to drink immediately after waiting for the treatment to finish.