Reverse Osmosis System-A 10 If You Need One-But Do You Need One?

by David Eastham

You cannot beat reverse osmosis water units when it comes to cleaning up water contaminated with salt. In that case they are worth the headaches. However, 95% of us get our water for a city utility company or from a chlorinated well that does not have a salt water problem. For us there is great news! Newer systems, called selective filtration, are simpler to install and use, cost less and produce healthier water than reverse osmosis. We will check out both systems in this article and you can decide.

The RO system works by forcing water against what is called a semi-permeable membrane. The membrane's pores are so tiny that any object larger than a molecule of water will not pass through it. Often, water molecules cannot get through either and, usually, this water is simply discarded along with any minerals or contaminants that have been screened. In general, these systems reject two or three gallons of water for every filtered gallon produced.

The fact that minerals are screened out is why they were so popular with people who were also dealing with the things like iron and sulfur in their water. It is also the reason I implied above that the SF systems will produce healthier water.

It turns out that removing ALL the minerals is not a good thing. The body needs some trace minerals like calcium for strong bones and teeth and potassium for regulating the heart. The water become slightly acidic when all the minerals are removed and the acidic water will leach out some of the body's calcium to make calcium carbonate in order to return to a neutral pH.

Health experts also tell us that cancer cells seem to grow only in a slightly acidic environment and, for that reason, they feels there is a long-term health risk associated with drinking demineralized water.

If you do decide on a RO system, be certain it comes with a carbon filter. This is because chlorine, a deadly poison, along with herbicides, pesticides, THMs, SOCs, drugs, etc., are made up of molecules smaller than water's so they will not be removed by reverse osmosis systems.

If the water pressure in your home is too low, reverse osmosis systemes will require the addition of an inline booster pump in order to operate properly.

If you want to have more than just drinking water from an RO system you will need to add a storage tank, since these systems only filter a gallon or so of water per hour. In order to keep a constant pressure on the system a tank with a diaphragm is normally used.

By the time you put all the storage tanks, extra pumps (if needed), and filters together you are going to have a good sized unit. Anytime you have a lot of components you are likely going to be dealing with extra initial and operating costs, and maintenance issues.

Anymore, I feel like using a RO system where you could have used selective filtration is like hunting flies with a cannon...they're clunky, expensive and give a dangerous result.

Now, let's look at an alternative to reverses osmosis, the selective (or multi-stage) filtration system.

In selective filtration systems, carbon is mixed with a filter resin that has been chemically charged, and this mixture is then compressed into a solid block that has very small, submicron pores. The carbon, or course, removes chemicals and drugs that might be present in the water.

This carbon has a huge filtering capacity. They say a cubic foot of compressed activated carbon like this has a filtering area of five square miles! Plenty of capacity to clean up chemicals, and it also takes care of things like Cryptosporidium and Guardia (chlorine-resistant Cysts), and
any remaining inorganic contaminants, with the submicron pores.

And the chemically charged filter resin...what does that do? When heavy metal compounds such as mercury or lead come in contact with this resin, their positively charged ions break their bond with water and snap onto the resin like little magnets. Because of the difference in their molecular structure, the lighter metals such as potassium and calcium don't react and remain in the water.

You noticed these systems don't have bulky storage tanks, they don't need booster pumps or electricity and, if they are correctly installed, they produce good, healthy water (all trace inerals intact) virtually without maintenance.

Be sure you consult a technical representative for any system you are considering if the water you want to treat has extreme problems. They folks will invariably have a good solution. Also, please note that selective filtration is not designed to treat salt water.

David Eastham has done extensive research on such topics as selective filtration to discover the most economical way to get (http://www.Good-Safe-Water.com) good, clean drinking water. Here are his picks as the best dollar for dollar buys, and (http://www.Good-Safe-Water.com) the best products overall, in home water filtration systems.