Nature Pure Filters
Copied from another site:-
"Not sure if you are aware, but some Nature Pure filter kits and replacement filters have been supplied incorrectly over the last 2 years.
The correct filter for motorhome use is part number 420420, which filters 0.4 microns. The filter supplied by Nature Pure is part number 420422 which only filters 3 microns. The part number can be found on the black cap on the bottom of the filter.
The 3 micron filter DOES NOT filter out bacteria or virus, therefore needs changing to the 0.4 micron filter if you are to stay protected.
The kit we purchased at the NEC in October had the wrong filter supplied, I only found out from a thread on Fun. I am in the process of trying to get a correct filter supplied from Nature Pure, hopefully FOC".
Comments
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Never used filters, but I am curious - at 0.4 micron (which I assume is a average pore size, so some larger some smaller), you would not remove all bacteria, for example Cholera, E. Coli, and Salmonella are typically between 0.2 & 0.5 microns and very few viruses, such as Hepatitis A, Rotovirus and Norwalk virus which are typically between 0.005 & 0.3 microns.
Do you use chemicals as well ?
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The question of filters is right up there with Supermarket fuel CJ.
To filter out viruses you need an effective pore size of approximately 20Nanometers a
It is generally accepted that a filter that will remove bacteria is 0.2micron. But going back into history then 0.45micron filters were used and in the real world a 0.4micron filter should be sufficient to filter water for ingestion rather than water for injection. An interesting example, a pharmaceutical that cant be sterilised by heat will normally be sterilised by filtering through a 0.2um filter. A standard test to check the sterility of the filtrate is to filter samples through a 0.45um filter and place that on an agar plate to see what grows. The reason using the larger pore size is it is retentive perhaps 1:10000 bacteria will pass through but it allows better passage of nutrients from the agar thus encouraging growth of anything on the surface.
A little secret filters aren't really the pore size stated they are not made by drilling tiny holes into a solid material, they are rated on the size of the organism that they remove in the case of a 0.2um filter Brevundimonas dimimuta which is approximately 0.2um in diameter when grown under the correct conditions.
Also the difference in flow between a 3.0um and a 0.4um filter would be huge.
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Thank you Boff - very informative, so good learnings for me there!
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As can be seen I only copied from another site for information for those it may concern.
It's purely coincidental but over the years I sold many thousands of water filters to large organisations and research institutes...yet for drinking purposes I have never used one myself and always use the local tap water!
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