I did not want to hijack someone else's thread, so forgive me if there's already an existing topic. At Wal-Mart today, I decided to pick some up (finally!) and found myself torn between the only two varieties they had. I opted for the cheaper of the two because: 1. It was cheaper and 2. It claimed to do 5 more quarts of water than the more expensive type.

I didn't want to spend a lot of time in walmart trying to google the differences, so I just grabbed the Coleman brand with the two vials (the brownish/greenish box shown below).

I am hoping some of you might be able to tell me what the differences are between the two, and which of the two might be preferable (and why).

My guess is that the primary difference is that one is chlorine based where the other is iodine based....? But what are the implications either way?

I appreciate any insight. I will try to properly link the two specific products I was comparing, never done a link before so hopefully it works!

the one i got

the one i almost got

The Coleman tablets you bought are Iodine tablets with a secondary additive to remove the Iodine taste.

The Portable Aqua tablets you show are Chlorine-Dioxide.

According to the CDC, both of these will safely kill most organisms found in groundwater, with the exception of Cryptosporidium. Iodine is ineffective in reducing Crypto to safe drinking levels. Chlorine-dioxide is effective if higher concentrations of chemical is used for extended treatment times.

As for taste, most people are used to a slight bleach odor and taste from public water supplies. At the normal dose (2 drops per liter), chlorine-dioxide treated water is palatable. Iodine-treated water is tolerable but has an unpleasant taste. The taste of either treatments can be made more palatable by adding a small amount of vitamin C. The chlorine odor and taste can also be reduced by leaving treated water in open containers or pouring back-and-forth between two clean containers to allow the chlorine to dissipate. Iodine does not dissipate over time.

Krista - you ROCK! Thanks this is the question that's been brewing in my mind. Thanks for asking!

If you're only going to carry one, what's it going to be?

I'm a complete new by to this but I'm attracted to the single tablet solutions, as opposed to the two step process. Am I just being lazy?

I learn something new here every day. Thanks Mark!

If you can get to an EMS (Eastern Mountain Sports)store or Bass pro shop,they sell MP-1 tablets,of which are chlorine dioxide,of which will be generally much more pleasant to use,than Iodine!1 tablet per Qt./litre of water for 4 hrs is the recommended dosage.Boiling is much more effective/quicker,If you can!

Chlorine dioxide.

Here's some reasons why:

Once opened, Iodine tablets expire after a year. 4 years if left unopened. Chlorine dioxide tablets are individually sealed and each tablet is good for 4 years if left as such.

Chlorine dioxide is effective against cryptosporidium, iodine is not. Both have a treatment time of 30 minutes for water that is clear and of roughly room temperature. The exception being water that is murky or very cold, in which a 4 hour treatment time is recommended for chlorine dioxide against cryptosporidium.

Finally, ingestion of too much iodine over time can lead to thyroid problems and iodine does not evaporate from treated water. Whereas, chlorine dioxide will eventually dissipate from the treated water if the container is left open and given ample time.

The big downside for chlorine dioxide is cost. They're more expensive than iodine tablets. However, if I was truly cost conscious I would be treating my water with liquid bleach anyway.....which is effective against all the same waterborne illnesses and parasites as iodine tablets, but is a lot cheaper. Like iodine though, liquid bleach is ineffective against cryptosporidium.

Thanks for the great input! I am now wishing I had spent the extra money on the other kind! I guess I can get some of those too, as these things are mostly for BOBs and/or vehicle kits. At home, bleach sounds good to me!

I had to research the crypto-bug thing on the CDC website, worth noting is that boiling the water before treating with the iodine tablets should take care of it.

Although, I am really liking the idea of the chlorine tablets, especially if they do dissipate over time from the water, as Paul810 noted! I like tasty water.

Boiling in and of itself will kill most common water borne illnesses. There are a couple things it doesn't work against, but none that I would really worry about for the purposes of water purification.

[It is worth mentioning, one notable thing standard boiling doesn't kill, is botulism spores. This is one reason why it's important to use a pressure cooker for home canning. While botulism toxin itself is killed by regular boiling, killing the spores requires a greater temperature than simple boiling can produce. A pressure cooker allows for those temperatures (some 250*F), thereby preventing the spores from producing botulism toxin.]

Because of the name of this thread, there's one warning I feel compelled to throw in here: Neither of these tablets 'purify' water, they only 'disinfect' it to some degree.

It's important to remember that water contains runoff from the surrounding land. If there are crops, there are agricultural chemicals in the water. The same holds true if there are manufacturing or mining sites upstream.

Bringing water to a boil will kill everything that either of these tablets will kill.

To remove other impurities, you will need a filter.

What do you guys think of these and why are they being sold as useful for treating water for pets?

ETA: I guess links are not allowed for some reason. It comes up "censored". It was an eBay listing for something called Aquatabs. 170783369698 if you are interested.



This guy has lots of 30 to 500 being offered. 500 is a lot of water treatment.

Excellent reminder and clarification, thank you! The survival mom blog just did a post about that very thing, improvised water filter. Three layers: grass, sand, charcoal.

Do you think that a simplistic one like that would be effective in the long run (combined with boiling)? Seems pretty easy to make... or are there other variables to consider that I am too 'right-brained' to consider?

A lot depends upon the nature of the impurities with which you must contend. A lot of my experience has been in relatively high mountains or lightly inhabited areas where industrial pollutants are trivial. Other locations may be different. It also depends upon whether you are talking short term exposure or long term use.

About twenty years ago, I spent a month in rural China on a caving expedition. We were way off the tourist circuit and depended exclusively on local resources and cooks. Our drinking water was treated exclusively by boiling by those cooks - standard practice for preparation of potable water at the time. Twelve of us lived locally for a month. Absolutely no cases of "Mao's revenge," which surprised me greatly. That is one reason why I am such a fan of boiling as a treatment method.

for you personally ... the water purification tablets may work. it just takes some personal discipline.

however it has been my experience that a LOT of normal people do not like the taste of water after it has been purified by iodine. So they just won't drink it. Hence they become dehydrated, and can get sick. we are spoiled in America by the existence of vast quantities of good-tasting water (often in bottled form). Once this becomes unavailable, people often "fall apart". This is a real problem if you plan on helping your family to survive in a long-term disaster. You would think that the logical human reaction would be "OK ... I understand I need to drink, so I will do what's necessary to avoid getting dehydrated". BUT that's not actually what happens in reality. People don't understand the seriousness of dehydration, and once they get into that state - they start going downhill. It can be a serious problem.

Experiment with ways to take the taste out.
Simple additives (like Tang orange juice powder) are not a good answer.
But keep looking!

Pete2

As Hikemore mentioned, the whole question of drinking chemcically polluted affected water largely depends on where you are and where your intended wilderness activities will take place.

In the areas I adventure in, there is no cause for concern of drinking such polluted water. Yes there is a concern for other natural water borne hazards which is why I use the Aquatabs to treat the water.

Boiling is always an option (and a last resort for me) if you are carrying a stove or alternatively, able to light a small fire and have the time to boil the water. Keep in mind that on a long hot summer day hike, how much water 2 or more people will require. Plenty of years of personal experience has shown that these water requirements can be measured in gallons per day. Whereas using tablets, the water can be treated on the move, meaning that we refill the water bottles as we go and add an Aquatab to each bottle. After 30 minutes, the water is ready to be used and there is no delay for having to stop and boil water.

In a true wilderness survival situation, I would rather allow tablets to treat my water while my focus and energy is directed to other concerns in order to keep myself and possibly others, alive.

Teslinhiker's post illustrates just how much circumstances can and should influence your choice of treatment method. I agree that on a long hike, particularly in the desert or during a warm/hot summer day, your consumption will be measured in gallons per day, not counting what you may consume during the evening to accomplish full rehydration.

In the desert and in any circumstance where water might be scarce, you would be prudent to carry the water (yup, all 16 pounds) with you from the beginning and then the quality of the water would not be an issue.

If all else fails, just slurp up the water from the natural source and restore your water balance. Whatever is in the water is not as bad as severe dehydration, which is deadly. I have done that a fair amount and have never regretted it.

I agree. The most common pathogens would take 3 to 5 days before the onset of symptoms, by which time you would hopefully be safe and have access to medical treatment. Also note that treatment does not necessarily remove or deactivate all organisms, it just reduces them to safe levels. So it seems the body has the ability to fight off infection, at least at lower levels of contamination.

I've often wondered if a person builds-up an immunity to these threats. When I was young I'd spend most of my free time in the woods, and thought little of drinking a few handfuls of crisp, clear water from a small fast-flowing creek or stream. I don't remember ever getting sick from it.

I don't think it is immunity...but luck that you never got sick.

For example, Giradia is very common and millions of people are infected by it every year. From the US CDC.

Giardiasis is a global disease. It infects nearly 2% of adults and 6% to 8% of children in developed countries worldwide. Nearly 33% of people in developing countries have had giardiasis. In the United States, Giardia infection is the most common intestinal parasitic disease affecting humans
Giardia infection rates have been known to go up in late summer. Between 2006-2008 in the United States, known cases of giardiasis were twice as high between June-October as they were between January-March.

Anyone may become infected with Giardia. However, those at greatest risk are:
Travelers to countries where giardiasis is common
People in child care settings
Those who are in close contact with someone who has the disease
People who swallow contaminated drinking water
Backpackers or campers who drink untreated water from lakes or rivers
People who have contact with animals who have the disease

In the context of this thread, unless it is a very dire life or death situation where you are incapacitated or do not have fire resources or water treatment tablets, it is always in the best interests of your health and well being to always treat your water while out adventuring.

I get what you are saying about chemical contamination, but I wanted to point out that in most of the reading I've done, mostly in the context of backcountry water treatment, I've noticed the term purification is usually applied to solutions capable of rendering water safe from viruses in addition to protozoa & bacteria. See this article for an example of this usage of the term.

For example SteriPens (UV), the MSR Purifier System (filter + chemical) and AquaTabs (chemical) are all considered purifiers in this context (as a side note, the full product name of the latter is actually Aquatabs Water Purification Tablets).

I've never noticed any the products I've looked at marketing themselves as rendering water safe from industrial pollutants, but really they are are geared for primarily for backcountry use. Frankly, based on the product information and other reading I've done I don't know which, if any, solutions would be a good defence against industrial or chemical contamination.

As a side note, I've found the following chart (taken from the article I linked to above) helpful:

I amjust now reading a source, the 2010 edition of Medicine for Mountaineering, which states, "The First Need filter has an absolute pore size of 0.4 microns; the Sawyer Viral Purifier has an absolute pore size of 0.2 microns. Both have been demonstrated to remove viruses as well as bacteria and parasites in studies conducted for the EPA." (p.66) At least in the USA, I understand virus removal is not an issue in the backcountry.

This book has a very thorough discussion of water disinfection.

That's very interesting, did it by any chance cite a specific EPA study that could be looked up online for more information?

I ask because it is presenting different & conflicting information than I've seen before. For example, the CDC's guide for backcountry water treatment says "Filtration is not effective in removing viruses." And in it's guide on household water treatment, it looks at different classes of filters and rates their effectiveness. It says:

• microfiltration (.1 micron): not effective removing viruses
• ultrafiltration (.01 micron): moderate effectiveness removing viruses
• nanofiltration (.001 micron): very high effectiveness removing viruses

However, as far as I've seen (including the models quoted above from Medicine for Mountaineering) backcountry filters all would fall into that microfiltration category. This CDC information is consistent with the information I've seen presented by several different sources.

As a side note, we mentioned chemical contamination earlier and the CDC only rates nanofiltration as moderately effective at filtering chemical contaminants. So, based on that, it seems likely that backcountry filters wouldn't do anything for water with chemical contamination.


That's my understanding as well. I understand you are much more likely to run into water with potentially harmful bacteria or protozoa than you are to run into viral contamination. That said, viral contamination is possible mainly due to contamination from human and animal waste.

Unfortunately, those studies are not cited, as far as I can tell. Perhaps the manufacturers have the reference. Evidently, there is not consistent agreement on the filter size that is effective for viruses, although it would be hard to argue against the proposition that smaller is better. It's situations like this that just get my water boiling. Good thing I like tea.

I should have looked at the 2 models quoted a bit more closely before assuming either were typical backcountry filtering solutions. As it turns out both are somewhat unique to the market (something worth noting).

The Saywer model actually has a .02 micron filter which would put it in that ultrafiltration category the CDC mentioned.

The First Need unit is a bit different, it says it has a .1 micron filter but it could be one of its other stages deal with viruses (its literature didn't specify how exactly viruses were dealt with).

The EPA portion I believe refers to the EPA standards for water filter and purifiers; both companies say their products have been independently tested and have been shown to meet these standards. I found these standards described here.

Since both these products are designed to remove viruses (and therefore marketed as having the ability) they belong in a different class than the filters most of us would find at the local MEC or REI store.

The OP's question was on the comparison of water purification tablets and if one is really all that worried or concerned that tablets do not kill viruses then the water should be boiled. And like Hikermore mentioned, I also like my tea.

I'm totoally agree with you.You'r 100% good here that there is not effective agreement on the filter sizing that is effective for viruses, although it would be challenging to declare against the challenge that little is better.
I agreed what's said above!!!