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Re: First Need and Carbon

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  • Don Johnston
    ... I am also proud to say I own a First Need. I hear you and for what it is worth this is the basis of my opinion: The design of the First Need element has 3
    Message 1 of 1 , Sep 14, 2000
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      > The First Need has a carbon
      > element. I expect different element designs with carbon vary in their
      > ability to absorb chemicals and may work better on some chemicals than
      > others. The First Need recomended food dye test is not necessarily a
      > valid test on other filters.
      >
      > Photon

      >I think this is incorrect. I have a First Need, and I've looked at their
      >lit;
      >they have no carbon element. The First Need has a pore size of 0.1 micron
      >and
      >filters out viruses, that's why they van call it a purifier. It will filter
      >out the blue dye provided. I also have a PUR Hiker, it has a pore size of
      >0.3
      >micron, and will not filter out viruses, that's why they can only call it
      >only a filter. It will not filter out the dye.
      >Craig

      I am also proud to say I own a First Need. I hear you and for what it is
      worth this is the basis of my opinion: The design of the First Need
      element has 3 key design features: 1 Microstraining down to 0.1 micron
      (0.4 micron absolute) and while some viruses may be trapped if they
      happen to be attached to a large enough particle many will fly right
      through so this is not the main mechanism which removes viruses. 2
      electrochemical separations (attracts colloids and other particles by
      appositely charged surfaces in the filter) which is probably the
      mechanism that removes viruses. 3 Broad Spectrum Molecular Capture which
      is what removes chemicals like food coloring. Probably all three design
      elements have some role in this filters ability to remove viruses.

      This is a Quote from the Web site on Broad spectrum Molecular capture:

      Broad Spectrum Molecular Capture mechanisms remove chlorine and organic
      chemicals including specific
      pesticides, herbicides, and solvents, along with foul tastes, bad odor
      and color. Importantly, valuable minerals
      and electrolytes remain in the water. These minerals and electrolytes
      are essential to good health and to good
      tasting water.

      In layman's terms the material that can do this is what is generally
      referred to as carbon. Carbon has the ability to bond with chemical
      molecules. or rather chemical molecules bond with carbon when they come
      in contact. In the First Need, Carbon is not a separate element it is
      used through out the filter structure.

      http://www.generalecology.com/

      I really liked my first need but I haven't used it in years because it
      really does a little too good a job. Mine would get significantly hard
      to pump fairly quickly.

      Chemicals are made up of molecules to small to be removed by filtration.
      Filters which do not contain carbon make no claims of removing
      chemicals, taste, color etc. (Dye being a color) The Pur filters do not
      contain any carbon in their main element and the stop top which can
      contain carbon is there for removing Iodine taste thus they make no
      claim to removing chemicals or colors of any type. In fact the recall of
      the stop top is because they used carbon of a design that did more than
      remove taste it also removed enough Iodine from the water that the
      company found it reduced the effectiveness against viruses. If the
      carbon filled stop top is used there is some chance it could remove food
      dye but depending on the age and design of the carbon material it may
      not. Without the carbon it has no chance of removing a chemical like
      food dye thus in my opinion removal of food dye is not a valid test of
      filters which do not incorporate carbon.

      The chemicals that bond with the carbon take up space on the surface of
      the carbon. Eventually the surface of the carbon will be covered and
      additional chemicals will simply slide right by. This can explain why
      one persons sweetwater can remove the dye and another can't. One persons
      cartridge may be old enough that its capacity to absorb chemicals has
      reached its limit while the other persons element still has surface area
      left. Carbon is used in the Sweetwater but not as the primary filter
      material for removing microorganisms and bacteria. The primary filter
      material is surrounded with carbon internally. They only claim to use
      the carbon as a taste filter. There is a picture on Cascade designs web
      site: http://www.cascadedesigns.com/tech_pages/guardian_filter.html

      Photon
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