Why Do Reverse Osmosis Systems Have Pre-Filters?

On of the most common questions that I answer isBut here is the kicker - the chlorine that your water
why a reverse osmosis system has a sediment filtercompany puts into the system to kill bacteria and
and carbon filters prior to the membrane.other organisms will destroy the membrane, making it
The answer is that it is to protect the moremore porous. Over time, the chlorine dissolves the
expensive membrane. The membrane is typicallymembrane and makes the pores larger. Pretty soon,
made of cellulose acetate. This filter, though physicallythe membrane is not doing its job as a filter, which
strong, does have some weaknesses.allows water to pass through. Next thing you know,
The sediment filter is used to remove dirt and otherthe water you drink has increased levels of the
particles which can coat the membrane, which willcontaminants that you do not want.
reduce the efficiency. Think of the sediment filter asIt is important to change out your sediment and
an air conditioning filter. When you first put it in, it iscarbon filters more frequently than what most
clean and captures a lot of dirt. As the filter getsmanufacturers "suggest". Just like a car air filter, you
loaded, less waster can pass through due to pluggingneed to change it more than once a year if you drive
of the pores. This situation occurs at the membraneyour car on dusty roads to keep your fuel efficiency
as well. What will happen is that the membraneup. The same is true with your Reverse Osmosis
becomes less efficient and will actually treat lesssystem. Most public water companies start increasing
water over time.the chlorine additions to the water to fight bacterial
As for the carbon filters, most folks know that theygrowth as the water temperature increases. I usually
will remove organic contaminants. The organicrecommend that the sediment filters get changed
contaminants include hydrocarbons, chlorineevery three months and the carbon filters every six
complexes and other similar chemicals, which canmonths so that the Reverse Osmosis system is
have a detrimental effect to your health.operating a most efficiently.