Water Purification Tablets

Hi,

The 4-hour wait time is for worst case cold and contaminated water. In the US you probably never have to wait that long.

Normally a 15-20 min wait time is sufficient. The different packagers of the tablets use different marketing strategies, although they are selling the identical item. Those less infiltrated by lawyers recommend the shorter wait times. I recall one of them even has a table listing different wait times for different water conditions (temperature, contaminant, cloudiness, etc).

I use tablets all the time and never wait more than 20 mins for relatively clear water.

Actually all the recommendations come from an EPA study you can find on the web. There you'll find complete information on wait time versus log reduction of various contaminants, temperature, cloudiness, and a bunch of other factors.

Most of my trips are in the Oregon Cascades and a lot of my water comes from snow melt or high alpine streams – both of which I’ve drank unfiltered before without any “known” effects. It sounds like I could probably go with much shorter wait times that the 4 hours, which makes me start to think tablets are a worthwhile option.

Thanks for the advice

I just picked up some 'aquatabs' which weigh 1.4g for a strip of 10 one litre tablets. For a weekend I'd probably take 20 tablets to be safe, which is 2.8 or 0.1oz.

http://www.aquatabs.ca

I use Aquamira water purification tablets with great success. I recently completed a Wonderland Trail thru-hike using the tablets. I agree with others that the 4 hour wait time is not always necessary. I try to treat as long as possible, but there are times when 20-30 minutes is fine and you can't wait. I have not had any ill effects with the shorter wait time. I brought a 1L Platypus and a 1 quart Gatorade bottle and rotated between the two. With record temps in Seattle of 103 degrees during my hike and likely in the low nineties on the trail, I ended up carrying more waster than usual but this treatment system worked well for me.

Is crypto a significant concern? My understanding is that tablets don't stop this.

Tablets kill crypto…but it can take up to, or over 4 hours.

remeber that cold stream water or snowmelt is going to warm up once you remove 1 quart of it and let it sit in a bottle at air temps.

on any given trip ive been on recently (during this summer, which in Phx wont end until October 31st :(
the water can be in the 45-60° range and quickly warm up to the 82° outside air temp (and thats about 102° in direct sunlight)

Katadyn MicroPur – approved, not just recongnized, by the EPA

My chlorine tablets say you can wait a few hours and they'll kill giardia, but they say chlorine tablets haven't been proven to kill crypto. I wonder if they are just playing it safe?

FWIW, In their MIOX literature, MSR says that chlorine tablets (and iodine) don't kill crypto. That's why they called this device the MIOX (mixed oxidents) rather than the ChlorinOX (or whatever) because it does more than create chlorine. I dunno if they are just using the lack of absolute proof in the literature to support their product though.

I'm not terrible worried…just curious really

Dan – as per Micropur Tabs (Chlorine based):

"The Only EPA Registered Purification Tablets on the Market – effective against Cryptosporidium, Giardia, bacteria, and viruses. The only disinfection system effective against viruses, bacteria, cryptosporidium, and Giardia. Fresh tasting water – no unpleasant taste. Easy to use tablets. The same proven technology that is used in municipal water supplies. Lightweight and compact – ideal for traveling, lightweight backpacking, and emergency use."

More info here:

http://www.katadyn.com/fileadmin/user_upload/katadyn_products/Downloads/Water_Guide_EN.pdf

That's interesting….I wonder if they are the only tablets effective against crypto, or just the only tablets that someone has spent the time & effort to test? Either way, I usually would rather drink sooner and risk crypto vs. waiting 4 hours or so I guess crypto is a red herring.

> The only disinfection system effective against viruses, bacteria, cryptosporidium, and Giardia.
Well, that's a lie anyhow.

> Fresh tasting water – no unpleasant taste.
A bit like a swimming pool…

Cheers

Be careful to make a distinction between chlorine-based treatment (bleach) and chlorine dioxide (ClO2) treatment.

The active agent in the former is chlorine, and the active agent in the latter is oxygen. The ClO2 dissociates in water and yields O2 ions, which kill the nasties, including Cryptosporodium if the contact time is long enough.

Actually the relevant measure is concentration (C) times contact time (T). This is referred to as CT in the EPA surface water treatment studies, which are the basis for all manufacturer's recommendations.

Most of my trips are in the Oregon Cascades and a lot of my water comes from snow melt or high alpine streams – both of which I’ve drank unfiltered before without any “known” effects. It sounds like I could probably go with much shorter wait times that the 4 hours, which makes me start to think tablets are a worthwhile option.

Water under those circumstances doesn't normally need to be treated at all — the lightest treatment option of all. Despite all the hype from filter companies, the water at elevation in the Western US is pretty clean. Use your head of course (don't drink downstream from the herd), but you should be fine just drinking it straight.

I've heard that mountain goats and bighorn sheep can carry Giardia all over the place, even to high elevations. But Jim seems to think not. I have no clue. Anyone care to comment?

the aquatabs previously mentioned don't touch crypto.