watermatters

• Shower Filter Comparison for Metro Vancouver

  Monday, December 6th, 2010

  This shower filter comparison is the result of our search for the best shower filter – especially for use in Metro Vancouver where tap water is soft, may contain very fine particulate and is disinfected with chlorine.

  Why use a shower filter?

  Chlorine is a poisonous gas that we inhale and absorb through our skin while showering.  The rate of chlorine exposure in a shower is many times greater than from drinking chlorinated water.

  How chlorine shower filters work

  Shower filters utilize either a chemical or a galvanic action to neutralize chlorine. Manufacturers use KDF, ascorbic acid, charcoal or calcium sulphite to accomplish this.

  Shower filters and drinking water filters are not interchangeable

  Shower head filters must perform with hot and fast-flowing water. Their challenges and design requirements are quite different from drinking water filters which are only meant to be used with cold water running at slower rates of flow.

  Characteristics of the best chlorine shower filters

  We considered the following factors for determining our top choice of dechlorinating shower filters:

  • Filtration media This is the material inside a shower filter that neutralizes chlorine. There are 4 different types of media commonly used for dechlorinating shower filters: KDF, vitamin C, calcium sulphite and charcoal. These vary in capability and longevity. See details below.
  • Internal design The better shower filter companies incorporate proprietary innovations in the internal design of their products that maximize effectiveness of the media and minimize pressure-drop and pre-mature failure due to the clogging impact of sediment in the incoming water.
  • Sturdy construction Because of the high pressure and heat involved, the casings of shower filters can crack, split and even explode, if not well designed.
  • Aesthetic and user-friendly options Functional and style options can save head room, adapt to different installation situations and incorporate adjustable spray settings.
  • Environmental impact Replaceable cartridges have less impact on our landfills than disposable one-time-use units. The effect of effluent water on marine life and the possibility of recycling spent filtration media are also important considerations.

  We investigated the effectiveness of different types of filtration media and tested the design of various dechlorinating shower filters. This is what we found…

  KDF shower filters

  KDF is a granular or fibrous combination of copper and zinc, two dissimilar metals that generate a galvanic charge strong enough to convert chlorine into a harmless and soluble chloride.
  KDF shower filters can process thousands of gallons of chlorinated water because kdf does not dissolve or adsorb* – two factors which limit the effectiveness of other types of shower filters.
  KDF is most effective with hot water -the hotter, the better.
  KDF’s effectiveness can be compromised if there is a lot of sediment in the water entering the filter. If not properly designed, dirt can coat the surfaces of the kdf granules, interfering will the galvanic action.
  KDF does not remove organic contaminants, such as THMs (trihalomethanes).
  Although capable of removing heavy metals such as such as lead, cadmium, arsenic, and mercury, it cannot do this (as claimed by some KDF shower filter companies) with the amount of KDF used in a short filter body, and at a high flow rate, as occur in a shower filter.
  KDF is bacteriostatic** and tends to reduce fungus and mildew build up in the shower.
  It eliminates further occurrences of blue-green staining caused by copper leached from metal pipes by acidic water. (This is common in the Metro Vancouver area).
  KDF granules can be recovered for reuse. watermatters is currently looking for an end user. Zinc and cooper make brass – great for sculptures!
  Some KDF shower filters meet NSF standard 177 for sustained chlorine reduction.

  Vitamin C shower filters

  Vitamin C is highly effective for reducing chlorine in a broad range of water temperatures
  Ascorbic acid is the synthesized form of vitamin C used for shower filters (and possibly sodium ascorbate). Ascorbic acid reacts with chlorine, converting both into a benign combination of inorganic chloride and dehydroascorbic acid.
  Vitamin C is extremely soluble making it very fast-acting and well-suited and easy to use for controlled volumes of water like baths.
  Vitamin C leaves no spent material for the landfill and is actually beneficial to fish***, the end recipients of our drain water.
  Ascorbic acid may make your bath or shower mildly acidic, a beneficial property for contact with the skin’s acid mantle. Over time, this acidity could have an abrasive effect on enamel bathtubs.
  Vitamin C does not neutralize THMs and other chlorination by-products present in chlorinated bath and shower water. It is used in lab tests that require efficient chlorine removal without influencing the presence of chlorination by-products.
  Vitamin C benignly washes away as it is used. Only the housing remains at the end of the cartridge life-cycle
  Presently there are no Vitamin C shower filters certified by NSF.

  Suphur-based shower filters

  Calcium sulphite is a very effective chlorine scavenger in a broad range of water temperatures.
  It is relatively soluble limiting how long it remains effective.
  Some people are allergic to sulphur-based compounds.
  Sulphur-based compounds reduce oxygen levels in effluent water, not a beneficial influence on fish.
  The active suphur-based dechlorinating agent is washed with use leaving any aggregate and the housing remaining once the media is spent.
  To date, there are no NSF-certified calcium sulphite shower filters.

  Charcoal or carbon-based shower filters

  Charcoal is loose granular carbon.
  Carbon filters are very effective de-chlorinators with cold water applications involving slower rates of flow such as with drinking water filters.
  Carbon filters by adsorption* and is not suitable for hot water applications which cause the too-quickly exhausted carbon to ‘dump’ adsorbed contaminants back into the water stream.
  It fouls so quickly in hot water conditions that bucket loads would be required to sustain any benefit.

  Our top choice for your shower filter

  Shower filters must perform efficiently for thousands of gallons of hot running water. We feel most confident in the consistent and lasting effectiveness of a premium quality KDF shower filter. Our top choice is Sprite KDF shower filters which utilize KDF supplemented with Chlorgon®, their own sulfur-based formulation. Most Sprite shower filters are certified by NSF to Standard 177 for effective and sustained chlorine reduction. Sprite is a well-reputed California-based company with 30-odd years of experience in shower filtration and an impressive list of innovations to its credit. It also offers the best choice of styles and user-friendly options in the industry.

  Our top choice for de-chlorinating your bath

  VitaBath tablets are our top choice for de-chlorinating bath water. These vitamin C tablets couldn’t be easier to use. They are effective and fast-acting.

  Shower filters and THMs

  Chlorination produces many by-products that are known carcinogens. THMs (trihalomethanes) are the most prominent and researched group of these by-products. Unfortunately, to date we have found no shower filter that is able to neutralize THMs and other chlorination by-products. Carbon would be the exception except that, as mentioned above, it cannot sustain this benefit in hot water conditions.

  Shower filters and chloramine

  Chloramine is a disinfectant consisting of chlorine followed by ammonia. Although less effective as a disinfectant than chlorine, by adding ammonia fewer (and different) harmful disinfection by-products are formed. It is now commonly used instead of chlorine by many municipalities in North America, including Victoria, Abbotsford and Mission. (This method of disinfection is not used in Metro Vancouver.)

  Chloraminated water is already in a ‘reduced’ state by virtue of ammonia. This means that its reactivity with other substances has already been minimized. Consequently KDF does not reduce it.

  Some Vitamin C shower filter companies claim to eliminate chloramine, presumably by drawing it into the Vitamin C. However they fail to explain what happens to the chloramine once the Vitamin C dissolves. Our understanding is that chloramine is best removed with activated carbon via adsorption* however the sheer volume of carbon required to do this effectively for a hot shower is prohibitive, as mentioned above.

  Shower filter connection sizes are standardized in North America

  Virtually all shower filters, their pipes and fittings are a standard size in North America. The standard interior diameter is ½”. This means that a new shower filter should fit your existing shower pipe and shower head.

  * ‘adsorption’ is accumulation on the surface of the filter; chlorine is attracted to the carbon surfaces. ‘Adsorption’ is not the same as ‘absorption’.

  ** ‘bacteriostatic’ is the capability to inhibit further growth of bacteria. It is different from ‘bacteriacidal’ which is the capability to kill bacteria.

  *** Greg Peterka, Chlorine Concerns and the Endangered Species Act: Vitamin C and Fish

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