That's right, reverse osmosis water units are hard to beat when you have a problem like salt in your drinking water supply. But most of us don't have that problem; we get our water from a municipal supplier or from a chlorinated well. And, for those people, I've got good news indeed. You will get a better result from selective filtration systems than you ever could with reverse osmosis. In today's article we will examine both systems and how they differ. Then you can decide which one is best for your situation.
Reverse osmosis (RO) systems work by pushing water against a semi-permeable membrane with pores so small that only objects the size of a water molecule, or smaller, will pass through. As a matter of fact, the pores are so small they will even reject a large part of the water itself along with minerals and most contaminants. In most RO systems, the rejected water is simply wasted. Typically, this amounts to about two or three wasted gallons for every gallon filtered.
Some people throughout the US are also dealing with excessive minerals in their water and the fact that RO systems remove these minerals is another reason people have liked them. But, too much of a good thing can be bad.
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.
Since cancer cells seem to prefer environments which are slightly acidic, some health professionals are now questioning the wisdom of drinking such water over a long period of time.
Reverse osmosis will not remove contaminants such as drugs, chlorine, THMs (chlorine byproducts-carcenogens), herbicides, pesticides, SOCs, etc. because molecules are very small and will pass through the membrane. The EPA recognizes activated charcoal as the best filter for removing these compounds and you must be certain you have one if you go the RO route.
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.
You also will need to have a storage tank with these systems. RO systems only filter about one gallon, or less, an hour. At this slow rate the systems need a way to store the water needed for bathing, doing dishes, or laundry, whatever. The solution is a diaphragmed storage tank in order to keep pressure on the line.
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.
For most of us, using an RO system where you could use selective filtration is like using a backhoe to get a little crabgrass out of your yard. Sure, it'll get the job done, but the ensuing pain won't be worth it.
As an alternative to reverse osmosis systemes, let's take a look at selective filtration. This is also known as multi-stage filtration.
Carbon is also used in these systems to take out any chemicals and drugs present in the water, however, this carbon has been blended with a filter resin that is chemically charged and the whole thing is extruded into a solid carbon block containing very fine, micron sized pores.
It's interesting that scientists say a solid block of activated carbon, one foot square on each side, has an adsorption area of five square miles! No wonder is does so well with chemicals and it still has plenty of capacity in the tiny pores to clean up chlorine-resistant cysts, like Cryptosporidium and Guardia and any remaining debris.
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 minerals intact) virtually without maintenance.
If you have a really gross water condition to remedy, it is always wise to talk to a technical representative for any filter system you are considering. These techs are great and they almost always have a solution. And, please note, selective filtration is not designed to treat brackish or salty water.
Reverse osmosis (RO) systems work by pushing water against a semi-permeable membrane with pores so small that only objects the size of a water molecule, or smaller, will pass through. As a matter of fact, the pores are so small they will even reject a large part of the water itself along with minerals and most contaminants. In most RO systems, the rejected water is simply wasted. Typically, this amounts to about two or three wasted gallons for every gallon filtered.
Some people throughout the US are also dealing with excessive minerals in their water and the fact that RO systems remove these minerals is another reason people have liked them. But, too much of a good thing can be bad.
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.
Since cancer cells seem to prefer environments which are slightly acidic, some health professionals are now questioning the wisdom of drinking such water over a long period of time.
Reverse osmosis will not remove contaminants such as drugs, chlorine, THMs (chlorine byproducts-carcenogens), herbicides, pesticides, SOCs, etc. because molecules are very small and will pass through the membrane. The EPA recognizes activated charcoal as the best filter for removing these compounds and you must be certain you have one if you go the RO route.
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.
You also will need to have a storage tank with these systems. RO systems only filter about one gallon, or less, an hour. At this slow rate the systems need a way to store the water needed for bathing, doing dishes, or laundry, whatever. The solution is a diaphragmed storage tank in order to keep pressure on the line.
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.
For most of us, using an RO system where you could use selective filtration is like using a backhoe to get a little crabgrass out of your yard. Sure, it'll get the job done, but the ensuing pain won't be worth it.
As an alternative to reverse osmosis systemes, let's take a look at selective filtration. This is also known as multi-stage filtration.
Carbon is also used in these systems to take out any chemicals and drugs present in the water, however, this carbon has been blended with a filter resin that is chemically charged and the whole thing is extruded into a solid carbon block containing very fine, micron sized pores.
It's interesting that scientists say a solid block of activated carbon, one foot square on each side, has an adsorption area of five square miles! No wonder is does so well with chemicals and it still has plenty of capacity in the tiny pores to clean up chlorine-resistant cysts, like Cryptosporidium and Guardia and any remaining debris.
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 minerals intact) virtually without maintenance.
If you have a really gross water condition to remedy, it is always wise to talk to a technical representative for any filter system you are considering. These techs are great and they almost always have a solution. And, please note, selective filtration is not designed to treat brackish or salty water.
About the Author:
David Eastham has done extensive research on such topics as selective filtration to discover the best way to provide good, clean drinking water. Follow him for his picks as the best dollar for dollar buys, and the best products overall, in water filtration systems.
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