RapidPure Filters Review

[Ross Bleakney]

>> The problem remains: if you guess wrong, your filter's function appears the same, but free pathogens now flow right through into your drinking water.

I remember one of the pump filters I owned (First Need if I'm not mistaken) had a little dropper filled with blue coloring. If you had doubts about whether the filter was working, you could put some of that in the (dirty) water, and make sure that the water came out clear. It seems to me that something like that would make a lot of sense, both for this filter, and others (e. g. other filters fail if they freeze).

[Roger Caffin]

> it would be nice to pop the cell out of my headlamp in the daytime to purify my water.
Now that is something I would try hard to never do.
Why?
Because there would be a serious risk of killing my headlamp battery in just one or two Steripen uses. The Steripen is great, but it wants ~1 A out of its batteries, and most batteries simply cannot give that. They die. On the other hand, there are not many 'headlamps' which are going to pull 1 A! So a battery which can no longer power a Steripen can probably give you quite a few more hours of light.

Cheers

[Roger Caffin]

Hi Ken

> Any problem with freezing?
Dunno, to be honest.
I would not expect there to be too many problems, because of the way the filter works. I will ask.

Cheers

[sean neves]

Roger, I use a Shining Beam S-Mini, which which weighs 1.5 oz. and accepts an 18650 cell. I use the 18650 cell in my light, as my main "do-all" solar battery for recharging my electronics. I am probably not typical of BPL in my electronic use, as I have been known to travel with cameras, hi def audio units for field recording and other such garbage. I use a 3400mah 3.7v lithium rechargeable for everything, sometimes two. The 18650 cell, unlike many other lithium formats, is a proven design with major manufacturers and tons of beta. It has literally twice the energy density of NIMH AA cells and can sustain up to 3 amps of continuous output. Perfect for a UVC florescent application.

Link to the light: http://www.shiningbeam.com/servlet/the-208/ShiningBeam-S-dsh-mini-XM-dsh-L-T6/Detail

Link to the cell: http://www.amazon.com/3400mAh-PROTECTED-Orbtronic-Rechargeable-Battery/dp/B00ANX46H2

Been thinking of doing a detailed post of my UL solar setup

[Roger Caffin]

Hi Sean

OK, interesting. Just don't put the 18650 batteries in an old Steripen Classic! Lotsa smoke …

> Been thinking of doing a detailed post of my UL solar setup
Get the lead out, get your a… into gear, and start writing! Today!
Yes, we would be very interested!

Do we get a review of the Shining Beam light as well?

I use a 12 v solar panel to recharge some of my batteries in the field – done so for years. Right now I am setting up a LabJack and a charging system to cycle various camera and phone batteries for life testing. Some of the Chinese clones of the Canon batteries work fine, while others seem to die. Not sure why.

Cheers

[Roger Caffin]

Official reply:
'Regarding freezing as long as the filter element is not wet when frozen there are no problems. If the filter element is wet and freezes we can not say there will not be damage.'
So – don't let it freeze.

re 'That's unique to this filter design'
Actually, I (RNC) think the First Need filter at least would have exactly the same problem – so not unique.

re tannic acid etc, official reply:
—-
Under conditions where there are both virus and tanni/fulvic acid in the water, the UltraCeram media will have a lower capacity for virus. This is because the charge of the tannic acid is more negative than that of the virus so it is removed first. To increase the capacity for virus when tannic acid is present you need 2 layers of UltraCeram or something else to remove the tannic acid. This is why our media alone cannot pass P-241 testing for very long.

This does not apply to bacteria. Bacteria are well retained by UltraCeram in the presence of tannic and fulvic acids.

This is another case where if the water is so potentially dangerous that this is an issue, then he/she should use an iodine or chlorine dioxide tablet in the water and allow the UltraCeram PAC to improve the taste and polish the water.
[RNC: or use a fabric filter and then UV.]

There is just no simple answer to purification filtration when you start dealing with complex waters.

As the RapidPure filter collects contaminants the flow will be reduced as there is a reduction in media surface area. When the flow is reduced to an unacceptable level it is time to change the filter element.

---

I must say, you don't often get such a straight-forward answer so quickly!

Hope this helps
Cheers

[karl hafner]

It should be easy to make a solution of a common bacteria and run tests to check. It would be very difficult to do for viruses. It is easy to plate and check agar plates.
It would be interesting to test a system after 10 liters 100 liters etc and see the results

[Roger Caffin]

Hi Karl

> It should be easy to make a solution of a common bacteria and run tests to check. It
> would be very difficult to do for viruses. It is easy to plate and check agar plates.

This is of course what the independant Test Labs do. There are standard protocols for this, and they do cover viruses as well as the larger bits. Quite expensive to perform the tests to the reuired standards.
The mfr has to have such test reports before they can claim that the device meets EPA standards. I have seen the Test Reports for the RapidPure filters.

Cheers

[Andy Jarman]

So you could put an iodine tablet in it and run two filters in series if the water was particularly obnoxious.

Two 'Scouts' ( a primary and a backup) and a blister pack of tablets should just about cover everything. Keep the old filter for your primary use, when it starts to clog throw it out and order a new back up.

In Western Australia the term 'river' applies to a variety of 'moist' situations north Americans would probably not recognise as water courses! So this is very interesting news for us.

[Bob Gross]

"Some of the Chinese clones of the Canon batteries work fine, while others seem to die. Not sure why."

I see the same thing. There must be some subtle difference in the chemistry.

–B.G.–

[Andy Jarman]

Just to clarify things, (I'm not always at my best before my morning coffee…)

The same filter is used in the

Water Bottle
Pioneer Straw* and
The Scout

only

The Water Bottle simply filters whats in the bottle.
The Pioneer Straw cannot be used to store water – simply to suck straight out of a puddle, whereas
The Scout is an in-line filter that can be used like the Sawyer to collect and store filtered water.

So while you need to buy the whole Scout/Water Bottle to start with, you just need to buy the filter inside it when it eventually clogs.

Different Combinations.
Considering you would need a scoop to collect water for your platypus/bladder when using the Scout in line, it could be the Water Bottle (which serves as the Platypus and scoop in one) is a lighter/cheaper option.

Could bring a backup filter without the Scout/Bottle casing which would further minimize weight.

Furthermore, if the bottle were smaller, say half a litre, one could save even more weight, just scoop the water more frequently.

A scoop and a wide mouthed platypus with a bottle filter inside it? No need for a valve and fancy lid with a platy?

Flow Rates.
The video on the Rapid Pure website gives a good illustration of the character of flow rates from the Scout filter – definitely an improvement on the squeeze – plus no viruses.

I'm hoping I'm not as dim as I sound in this post, thought I'd just open up a few angles on these things – currently looking at costs and implications.

*(not sure you mention the Pioneer Straw Roger – you mention the filter is referred to as the pioneer filter though).

[Roger Caffin]

I gather from RapidPure that they are aware of the problem with tannic acid. I have been told they are trying to do something about this. IF they succeed, they will let me know and I will report on it.

Cheers

[Colin Krusor]

Thanks, Roger.

Karl, there are simple tests that can be done for waterborne pathogens, including viruses. For protozoan parasites like Crypto and Giardia, there are fluorescent surrogate particles available (microbeads) that are similar in size and density and have similar surface properties to the parasites. These make testing of a filter for removal of parasites from a water sample very simple. In my lab I use "Dragon Green" and "Glacial Blue" surface-modified polystyrene microbeads that fluoresce green and blue, respectively, in the FITC channel on an epifluorescent microscope. A colleague of mine has published quite a bit on these, and validated them for testing of filters for removal of not only Crypto and Giardia, but also Toxoplasma from contaminated water.

For testing of a filter by consumers, I think a dye or pigment test (mentioned already in this thread) is the only kind that would be practical, but, in their simplest form, tests of this kind are limited in their sensitivity. A single Toxoplasma oocyst can cause you to become infected, for example, but you wouldn't be able to visually check for the presence of fewer than hundreds of pigment particles in your filtrate after a pigment test of a filter at home. I have doubts about the real value of any test that a person could perform without lab equipment.

[Ross Bleakney]

@Andy — Good post, but I have to quibble about one item:

>> Considering you would need a scoop to collect water for your platypus/bladder when using the Scout in line, it could be the Water Bottle (which serves as the Platypus and scoop in one) is a lighter/cheaper option.

I doubt it. A scoop could be as simple as a plastic bag, which weighs very little (the Ziploc bag I just throw on the scale weighs 3 grams).

I think the main advantage is convenience. A hard sided bottle (like the one shown) has its advantages. It is easier to put snow in there (although not as easy a wide mouth bottle). It is easier to pour other water into. It is easier to drink from. It is easier to hang off your pack.

As you mentioned, convenience is often a big factor. I know folks that carry pump filters and water bottles that they hang off of their pack. The RapidPure bottle seems like a superior system. They can fill quickly, but still have the same level of convenience (a level of convenience that is difficult, if not impossible, to achieve with the Sawyer system).

In general I think this is a great breakthrough. I will probably try some of these filters and incorporate them in my day hiking. I might stick with my Sawyer on backpack trips until I figure out the cost in terms of weight, though.

[Jerry Adams]

Dye or pigment test would be good if the particles were bigger than the pore size of the filter. But I think dye particles (molecules?) are very small.

If anyone knew of a relatively cheap dye particle that was a little bigger than the filter pores, that would be useful.

With this electrostatic filter, maybe this isn't an issue. Maybe the filter would trap the dye particles even though they're small.

I think Tannin is very small also. It goes right through most filters.

[Colin Krusor]

"With this electrostatic filter, maybe this isn't an issue. Maybe the filter would trap the dye particles even though they're small.

I think Tannin is very small also. It goes right through most filters."

Yes, that's what makes the RapidPure filters different from the Sawyer filters. The pores in the RapidPure filters are BIGGER than pathogens. Parasites, bacteria, and viruses (and tannins) would go through if it weren't for the attraction between their negative charges and the positively charged filter material. Anionic (negatively charged) dyes offer a low-sensitivity way to test that a filter of this kind is working because the dye ions are trapped by the positively charged filter media if there are positive charges left unoccupied. A better test would also involve negatively charged pigment particles similar in size to bacteria and parasites. Tannins are a problem because they compete with viruses and other pathogens for the bazillions of little positive charges in the filter. A lot of tannic acid could monopolize those sites so pathogens could flow through.

[Keith Selbo]

you can't tell when the rapid pure is no longer effective. it's useless.

I thru hiked the AT with Sawyer squeeze and two 1 1/2 L soda bottles. I backflushed the filter once a week. I could always suck water through the filter as fast as I could drink it, and I could always squeeze out 2 cups of water for cooking in less than 30 seconds. For most of us a higher flow rate is a waste especially if you don't know if the filter is still effective.

[Roger Caffin]

> you can't tell when the rapid pure is no longer effective. it's useless.

I am sure there are lots of competitors who who like to think so. But such a sweeping statement is rarely supported by any facts. And FACTS from independant Test Labs are what BPL needs.

Cheers

[Ian]

"you can't tell when the rapid pure is no longer effective. it's useless."

Same could be said for the Sawyer if it's exposed to sub freezing temperatures.

The issue with tannin is certainly concerning though.

Nice article Roger.

[Jerry Adams]

My impression from reading article was they're not quite "ready from prime time"

They don't have the lightest weight but still usable configuration

Yeah, all filters share the problem you don't know if they actually work. You just have to trust the testers.

[Ross Bleakney]

>> >> "you can't tell when the rapid pure is no longer effective. it's useless."

>> Same could be said for the Sawyer if it's exposed to sub freezing temperatures.

>> The issue with tannin is certainly concerning though.

>> Nice article Roger.

Yeah, and I'm not mistaken, the same can be said about First Need. So, basically, two of the most common filters ever used aren't perfect. First Need handled the problem by providing the dye, which works fine. For the most part, people just stopped using the filter when it started getting clogged. It seems to me that RapidPure could do the same thing.

To my mind, the biggest weakness of these filters is not the filters, but the housing. They are too heavy, and they lack the nice connection of the Sawyer.

Even with that, I may consider one of them, especially for day hikes. I'll have to dust off my old connecting tubes. Despite the weight, I think getting the big one (4.5 inch Explorer) might be worth it. Filling a dirty bag is almost always faster than pumping. But at some point, you need to filter the dirty water. When day hiking, I usually do that when we take a break, but it means finding a branch or rock to hang the contraption from. With this filter, I could just stand there and hold it and still be faster than a pump.

[Keith Selbo]

>So maybe, when the filter element looks a bit discoloured and it is several years old, you replace it? Nothing lasts forever. Reckon that might work?

>I am sure there are lots of competitors who who like to think so. But such a sweeping statement is rarely supported by any facts. And FACTS from independant Test Labs are what BPL needs.

I find the author's statements quite extraordinary. The effective life of this filter is finite and indeterminate. This is not disputed. It matters not that independent labs verifies it's performance when the filter is new. The filter provides no definitive indication that the end of life has been reached even though it still passes water that unsuspecting users then drink, and yet it is evaluated here as a serious alternative to filters whose performance is determinate. Of what importance is flow rate if you can't tell if the filter is doing what it's supposed to do?

>Same could be said for the Sawyer if it's exposed to sub freezing temperatures.

With one critical difference. Sawyer warns users of this problem and there is a simple solution. Don't let it freeze. When it's cold, my Sawyer filter resides in a plastic bag inside my shirt next to my body. On one occasion I forgot. I discarded the filter and used a backup chemical treatment for the rest of the trip.

[Ian]

Keith,

What I appreciate about this article is that the author provides a thorough synopsis of what it is and the technology behind it. I'm not reading this as a sales pitch nor is he trying to say that it's the best on the market. I'd personally rather rely on mechanical filtration instead of electrostatic adhesion.

For me, this filter wasn't on my radar before reading this article. I'll stick with my imperfect sawyer but I do appreciate BPL providing articles like this to help keep me in tune with what's going on in the market.

Have a nice day everyone.

[Jerry Adams]

figure how much water it should filter based on tests

figure out how long it will take based on your usage

write down on filter when this will occur and discard it at that time

[James Marco]

I agree. There are several water sources that could easily override the electrostatic component. Tannic impregnated water will often tend to leach minerals from the stream bed, eventually becoming clear in the process, that could cause the electrostatic charges to fail. Cysts and active bacteria have different cell walls, indicating different electrostatic charges. While a 3-dimensional molecule would allow both anion and cation attraction, similar to a water molecule, I don't see where this would give you more than 10-20 gallons of use (assuming it will get everything in the water) here in the NE corner of the USofA. I think I would stick to my Opti till they develope a two or three stage filter with an absolute pours size of at least .05micron or an indicator that tells when it stops being usefull.

[Author]

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