Filter Recommendation

[greg c]

I've been using my "dismal failure" MSR waterworks II since 1996. Simply bombproof. Roger – let's hope MSR continues producing these dismal failures. The world could use more of such egregious ineptitude :)

[Steve K]

Can't speak for anybody else but the Steripen Adventurer Opti has never, ever failed me.

I carry spare batteries and chlorine dioxide tablets and I have never been forced to use the tablets. I have taken it on many trips over the past three years and certainly treated at least 50 liters with it, although it is not always the only treatment I have had with me on trips.

[James Couch]

>A gravity flter is fine in forest land with convenient trees, but not so smart in treeless
>alpine regions.

Not such a problem really – I have done this many times, hang the bag on your pack/tent/trekking pole/ice axe, or if the feed is relativly fast just hold it up. I use the Platypus gravity-works, shortened the hose and use it above treeline all the time.

[Jerry Adams]

Put bag on rock, tube down to filter and clean water bottle. No need for tree.

[Jerry Adams]

"I've been using my "dismal failure" MSR waterworks II since 1996…"

I used the similar Katadyn or Pur.

Only problem with those is they're heavy. And pumping them is a bit of a pain.

[Roger Caffin]

Hi Greg

> I've been using my "dismal failure" MSR waterworks II since 1996. Simply bombproof.
Perhaps you haven't tried more modern gear, or used it in slightly silty water.

Their Hyperflow and Sweetwater units ARE disasters. Basically, pumped filters are obsolete today.
As for their MIOX electrolysis unit … – now thankfully discontinued. Wonder where they buried the excess?

Yes, I have tested and used all of them – and reviewed most of them.

Cheers

[greg c]

"Perhaps you haven't tried more modern gear, or used it in slightly silty water."

You jest, yes?

As for you reviewing or testing "all" of the MSR filters, that's merely a single opinion rendered on a small sample size. Such sweeping generalized statements as in your initial post make me smile.

[Pedestrian]

My experience with the MSR miniworks EX has been terrible as well. It was used mostly in the Sierra on group trips. I've had multiple failures despite the filter being "serviced" by MSR several times. The cartridge was replaced twice (under warranty).

After the third time it was "serviced", the MSR support guy admitted that the Miniworks EX is plagued by problems and I was offered a credit towards another MSR product.

On those same trips we also had Katadyn/PUR Hiker/Hiker Pro and Vario which performed perfectly; this was over a period of 2-3 years.

This was for groups of 8-10 people on trips lasting 7-8 nights. All filters need maintenance on longer trips with so much use but the MSR Miniworks EX was just dead weight after the first few liters.

I've since switched to some combination of AM/Steripen and am evaluating the Sawyer mini.

[Billy Ray]

I believe the MSR Miniworks EX was redesigned in the past year or two. It now gets rave reviews at the REI web site.

billy

[Roger Caffin]

> I believe the MSR Miniworks EX was redesigned in the past year or two. It now gets
> rave reviews at the REI web site.
Does REI sell them?

Cheers

[Zorg Zumo]

Katadyn Micropur tablets are nice. 4 hr wait is only for super-cold and turbid water. It will cysts in clear 60* water in 45 minutes or less.

[Billy Ray]

the rave reviews are on REI's web site so, yes, REI sells them

b

[Billy Ray]

The reviews I refer to are by REI customers who have bought and used the MSR filters… and then posted reviews at REI's web site…

b

[Marko Botsaris]

"so, if you wait around for 4 hours, you probably need to carry an extra pint or two of water,"

Yeah, I just don't. I follow the "G. Gordon Liddy" school on that. I wait 30 minutes only – "The trick is not minding."

[Yak Attack]

"Their Hyperflow and Sweetwater units ARE disasters."

May I ask why? Specifically what are the issues w/ the hyperflow? I have one, but haven't ever used it (yet)…

Thanks

[Pedestrian]

I spoke recently to MSR support ( < 1 month back).

According to MSR support, the Miniworks EX was last updated around 2006.

I bought mine around 2009 and like I said it just sucks and weighs around 14 oz. I do have the most current version with a new filter. But it is clogged again!

I'll freely admit that maybe I don't know how to use the Miniworks EX but believe me I've tried! Multiple times on several different trips – each time with the result that the filter clogged after pumping 3-4 liters. Others in my group also tried valiantly to make the Miniworks EX work but to no avail. The other filters we also had – different ones onn each trip: Hiker, Hiker Pro, Vario worked just fine with the same set of people using them and the same water sources.

If it's as finicky as that I just don't want to bother with it when there are far better alternatives.

And yes REI sells a range of equipment and not everything they sell is perfect.

Caveat Emptor.

[Jerry Adams]

Yeah, I just don't. I follow the "G. Gordon Liddy" school on that. I wait 30 minutes only – "The trick is not minding."

But that is sort of like drinking untreated water – although the 30 minutes will kill some bugs

If you drink untreated water, you may never get sick, but probably eventually you will. Depends on the individual and the water.

Since the Squeeze and Steripen are so light weight and convenient, probably smarter to just use one of them. Or you can wait until you get sick once and then start being more careful. A lot of people when they get sick, it isn't that bad. Some people, some times get very sick.

[Marko Botsaris]

"But that is sort of like drinking untreated water – although the 30 minutes will kill some bugs."

No, it isn't. I'm using the liquid (not tabs, which I've never used once) and following the instructions to the letter. So 30 min kills MOST bugs, not some.

It does get almost everything. I've just chosen to not care about the fraction of a percent issues. Also, I use filters when I go places where the water may be more questionable.

[Greg Mihalik]

Zorg:
"4 hr wait is only for super-cold and turbid water. It will cysts in clear 60* water in 45 minutes or less."

Giardia Cysts, not Cryptosporidium

"Depending on the temperature and pH, Cryptosporidium has been found to
be 8 to 16 times more resistant to chlorine dioxide than Giardia (Hofmann et al., 1997)."

" Finch et al. (1997) found 3-log inactivation of Cryptosporidium oocysts with initial chlorine dioxide residual concentrations of 2.7 and 3.3 mg/L for contact times of 120 minutes, at pH of 8.0 and a temperature of 22ºC."

This is for clear water.
3 log reduction = 99.9% reduction
3.3 mg/L ~ 3.3 ppm
22°C is ~ 72°F

"Reducing the temperature from 20°C to 10°C reduced the disinfection effectiveness by 40 percent."

10°C = 50°F
Increase the contact time to about 200 minutes.

[Zorg Zumo]

http://www.katadyn.com/usen/technical-support/micropur-support/

30 minutes at 68*.

[Derek M.]

Greg,
Thanks for posting some actual data.

I think the real question is whether a 3-log reduction in Crypto is really necessary for nearly all the real world backcountry water sources that backpackers use in North America?

This 3-log reduction means that if there are 1000 Crypto bugs in your water, you will only have 1 left after a 3-log reduction. How many Crypto cysts are there in an average infected sample from a backcountry water source? Would a 2-log reduction be sufficient 99.9% of the time? If so, you better believe that will take exponentially less chlorine dioxide exposure time to achieve.

How many individual Crypto bugs can most North Americans handle before becoming symptomatic? I have no idea, maybe somebody has done a thorough study though?

What is the incidence of Crypto and Giardia contamination in most North American backcountry water sources anyway? I wish there was more available data on this sort of thing so we could all make a more informed risk/benefit analysis when it comes to treating water (i.e. whether to treat it in the first place, and if so, how thoroughly it should be treated).

These are all just numbers games, and unfortunately, I haven't seen many numbers, so it's hard to make decisions that are actually reasonably informed in this arena, IMO.

[Greg Mihalik]

To confuse the issue even more….

I spoke with Chris V., Operations Manager at Katadyn about the chart they have under Technical Support – Micropure Tablets –

"Cysts" in column one Does include both giardia and crypto.

He assured me that Katadyn's independent 3rd party testing, per EPA requirements, shows a "log 3 reduction" – 99.9% – (or better)after 30 minutes in 20°C water. He attributes the lack of public data of those studies to the fussiness [my polite word] of EPA regulations.

Claiming not to know about findings in the 1999 EPA Guidance Manual Alternative Disinfectants and Oxidants, he could not explain the Large difference in contact times. (Referenced above as Fitch et al)

[Jerry Adams]

Column 1 is 20 C water. That's 68 F. My wilderness water is typically 40 F which is 4 C, the second column.

I wonder what clear water at 4 C would require.

[Greg Mihalik]

I'm not a lab tech.
Everything here is from searching web.
Whether you believe "Trust Me", from Katadyn, or the EPA tables for surface water tratement is up to you.

From the US EPA Disinfection Tables – for clear water running through a city plant –

Katadyn Micropure tablets are designed to provide 4 ppm (parts per million) to a liter of water.

The table above uses mg/L, which is very closely equivalent to ppm.
For Log 3 inactivation, if the CT = 800, divide by 4 ppm to get 200 minutes.

For example:Crypto, Log 3, 20°C, the CT is 348 (minutes)(mg/L).
Divide by 4 mg/L to get 87 minutes.

Pick your temperatures, and do the math.

If I'm wrong on this interpretation – Please jump in.

[Jerry Adams]

Making my head ache Greg…

see if I've got this right

log 3 means 999/1000 of the Crypto or Giardia are killed off – a reasonable disinfection level for fairly clean water. This should prevent you from getting sick, although statistically it's possible this might not be enough.

for Crypto, asuming the 4 ppm level you get from using Micropure, time to disinfect:
20 C = 68 F – 87 minutes = 1.5 hours
5 C = 41 F – 322 minutes = 5.5 hours
0.5 C = 33 F – 480 minutes = 8 hours

for Giardia
20 C – 4 minutes
5 C – 6.5 minutes
0.5 C – 16 minutes

If you double the amount of Micropur, you can half the time, etc.

If you assume your only problem is Giardia, treatment time is no big deal.

When I get water, it's almost always in the 32 to 40 F range, so Crypto treatment time seems unreasonably long. You could use 10x as much Micropur and reduce time by factor of 10 which would be reasonable. I bet the taste would be obnoxious.

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