View Full Version : Filters vs Chemicals

01-09-2003, 06:01
A comment on a diferent thread got me thinking about the weight of a filter vs aqua mira and so on. the statement was that if you weighed the weight against the immediate usage you might be able to save some weight by filtering. for example instead of a 70 oz hydration bag and aqua mira you might take a 1 qt nalgene and a filter. By tanking up on water while still at the source you only have to carry a small supply on the actual hike.

I dont have an accurate scale so would someone check this....

70 oz platy full = 5 lbs
Aqua mira = 4 oz

total 5 lb 4 oz

first need purifier 18 oz
1 qt nalgene 2 lbs

total 3 lbs 2 oz

I chose these scenarios because my normal is/was
first need purifier 18 oz
70 oz platy 5 lbs

hence I was carrying over 6 lbs

I dont think carrying only a quart on a hot summer day is enough by the time you factor in the half hour wait for the chems since you can sweat out that much just sitting in the shade and I am assuming that drinking untreated water is not a viable choice.

01-09-2003, 11:22
Your reasoning is kinda flawed.

32fl oz Nalgene weighs 5oz
First Need weighs 16oz
Total 1lb 5oz

70oz Platypus Bottle weighs 1oz
Aquamira system weighs 2oz
Total 3oz

Amount of water carried is an independant factor which does not apply. Except for the fact that you can carry twice as much with the Platypus/Aquamira system if you want/need to. Either way, your still saving 1lb 2oz by going the platypus/aquamira setup.

In addition to the platypus/aquamira setup, I use a custom filter setup consisting of first need parts, silt-stopper pre-filter, and platypus adapter. I will never rely on a commercial filter system again, until something for clogging is done. And ceramic cracks to easy in cold/rough conditions. Picture is available in the photo album.

01-09-2003, 12:09
while the amount of water is independant it is not a trivial matter. useing a system that allows you to carry less water which is inherently heavy is certainly worth consideration. The point is whether or not there is a net gain in the system and for that the amount of water carried must also be considered.

incidentally neither filters nor chems do well in freezing weather. The chemicals can take up to two hours to be effective! :eek:

01-09-2003, 12:40
Fro Aqua Mira you only have to wait for 15-20 mintues, not two hours.

Also some of the iodine bottles have space to put water in it, so that you don't have to wait the two hours for the chems to react in water.

01-09-2003, 14:02
Originally posted by PushingDaisies
Fro Aqua Mira you only have to wait for 15-20 mintues, not two hours.

Also some of the iodine bottles have space to put water in it, so that you don't have to wait the two hours for the chems to react in water.

Temperatures below 40 degrees may indeed require long contact time for chemicals to be effective. The 15-20 minute wait time for AquaMira probably applies to temperatues above 60F. PolarPur provides dosage information via the color bar on the bottle down to 40F. This accounts for the temperature dependence of the solubility of the iodine crystals (so that you get a 4 ppm solution in your liter of water), but contact time should still be lengthened as it takes longer for iodine to deactivate bacteria and cysts at colder temperatures. Below freezing the best option is usually boiling the water

01-09-2003, 16:14
I hate polar pure. It is absolutely disgusting. Chlorine is ok, as well as chlorine dioxide. I would also agree that boiling water in winter is the best means of disinfection. No pre-filtering needed either thanks to snow! Just bring a whisperlite and extra fuel.

01-10-2003, 06:53
I have noticed that at least some of the aqua mira advocates frequently admit to drinking untreated water..could have something to do with the wait time and taste issue.

FWIW.... ALL chemical reactions slow down as tempatures fall.

01-10-2003, 10:01
I had a first need filter, and it gave out on me. Attempting to use it as a gravity feed filter was useless as well.

So I stripped it and built a reliable setup (see my other post on water filters & aquamira, and a photo of the setup in the photo album).

Chemical treatment is how tap water is disinfected. Although contact time is longer in the cold, once it gets too cold I boil my water anyways. Aquamira actually doesn't take all that long if you plan it right.

1. Mix chemicals in the cap, and let it react for five minutes. While it's reacting, collect/pump your water.

2. By this time the Aquamira is ready. Dump it into your platypus (or bottle) and wait 15 minutes. While your waiting, shake the water out of your pump, and then purge it. Wipe it off and pack it up. Plan your snacks out so that one coordinates with water collection. Eat some salty food, and by then the water is ready, your thirsty from the salt, and you can gorge on water.

Or you can carry a commercial filter that will last an unknown amount of time, and can leave you high and dry when it clogs up, shatters due to water freezing in it (ceramics), or gets you sick due to a short circuit in the filter (happens often apparently). After the first need failing me, I'd feel safe with a commercial filter only if I carried a spare in the event of an un-backwashable clog. This means over a pound and a half of equipment.

My setup wth three replacement filters and the aquamira weighs 10oz.

01-10-2003, 20:16
and it's not the ambient air temp that counts it the temp of the water which in the mtns is always cold