Product Reviews Facts and Notes

In this article, we will look at reverse osmosis, distillation and multi-media block filter systems. You will discover drinking water filters vary widely in effectiveness, required maintenance, speed of filtering, and cost per gallon of water produced. You will also acquire the information you need to choose the best drinking water filter system for your family.

Realize at the start, that all of these systems are good, and, all of them are better than using your body as the filter, but, depending on the problems you are having with water, some are definitely better than others.

First let’s look at the reverse osmosis (RO) systems.

With these systems the incoming water is first pre-filtered, to remove the larger particulates, and then it is forced against a filter about the thickness of a piece of cellophane, called a semi-permeable membrane. The pores in this membrane are so small only particles smaller than a water molecule can penetrate it. For about ninety-five percent of the water problems people in the US face, this step works in a very inefficient and costly manner because:

1) Chemicals such as pesticides, drugs, chlorine, synthetic organic chemicals, etc. are not removed in the stage of the process since their molecules are smaller than water’s. A carbon filter must be used in combination with RO systems to finish the job.

2) Even under the required pressure, two-thirds or more of the water molecules cannot be forced through the membrane and they go down the drain as wasted water.

3) RO systems are slow, yielding less than one gallon per hour of filtered water and, consequently, they also require a storage tank to give an adequate supply of water for bathing.

4) Lead is a problem in our water and this stage does remove it. However, it also takes out the beneficial minerals such as calcium and potassium that our bodies need. This produces slightly acidic water that some health professionals think is unhealthy to drink on a regular basis.

RO reviews list maintenance as one of the biggest issues, followed by overall costs. Cost to produce a gallon of filtered water is between 18 cents to 24 cents.

Now, distillation systems (D) are next.

When the sun heats the earth the warm, moist air rises, cools in the upper atmosphere and falls back to earth again as rain or snow. That is a good example of distillation process.

With D systems, water flows over a heated surface, turns into a vapor that is sent to a cooling chamber where it condenses back into a liquid. Inorganic compounds such as minerals like lead, magnesium, calcium, etc. are removed in this process.

Distillation also destroys and bacteria present. Chlorine-resistant ‘bugs’ like Cryptosporidium and Giardia, are also removed at this point.

We noted the D systems removes harmful metals like lead, but they also remove the healthful minerals like calcium and potassium just like the RO systems.

A wide range of synthetic organic chemicals, drugs, etc. also escape the filtering effects of D systems. Since they vaporize at a lower temperature than water, they remain in the water the whole way. Because of this, just like the RO systems, these units must be used together with carbon filters.

Distillation like reverse osmosis is slow and incredibly wasteful, wasting up to 80 percent of the water used. Distillation produces water at a cost of 20 to 26 cents per gallon.

Lastly, let’s look at multi-media block filters or selective filtration systems.

Activated charcoal or carbon has long been viewed as the best technology for removing chemicals compounds such as chlorine, chlorine byproducts, herbicides, pesticides, drugs, etc., so, the earlier versions of these systems simply ran water through a cylinder filled with a granular form of activated charcoal.

However, these first systems:

1) Did not force all of the water to pass through the charcoal. Some of it was allowed to sneak between the filter’s wall and the filtering media and,

2) There was a lack of confidence over these filters’ ability to stop the extremely small, chlorine-resistant cysts such as Cryptosporidium and Giardia.

Both of these issues were resolved with the introduction of selective filtration utilizing multi-media block filters. This technology utilizes the advantages of the activated carbon by first blending it with a chemically charged filter resin and then extruding, or compressing, it into a solid block containing tiny, submicron pores.

The submicron pores filter out the cysts and the solid block structure prevents the water from channeling around the filter media.

Also, we know the activated charcoal easily removes the chemical contaminants from the water.

That leaves the special resin you mentioned…what does it do?

As water passes over the resin, it uses an ion exchange process whereby positively charged heavy metal ions in the water, like lead and mercury, are forced to break their bonds with water, and attach to the chemically charged resin like little magnets. Lighter minerals, such as calcium and potassium, are not affected, i.e. it leaves the good stuff in the water.

When you think of the “Rube Goldberg-ness” of the RO or D systems it is easy to understand why selective filtration technology is leading the industry. Independent laboratory tests have proven the produce the highest quality water and initial costs are more than competitive.

Operating costs are minimal as these systems are very efficient and economical, working without any extra pumps, electricity, storage tanks, etc. and they operate almost maintenance free, producing filtered water at about nine cents a gallon.

Just remember, whatever water filter you use, don’t let it be your body.