Reverse Osmosis Replacement Filters are simple, modular filters which are made up of media that’s used to capture and remove particles that might otherwise block the small spaces between the RO membrane layers as well as the submicron particulates that may foul the membrane surface.
They consist of pre-filters and post-filters with the pre-filters comprising of mostly a sediment filter which makes the first stage of the RO filtration process, a granular activated carbon filter that makes up the second stage and an activated carbon filter which takes the third stage in the RO filtration process.
These pre-filters can range from 10 to 5 microns and capture most of the sediments, chlorine, fine particulates and a number of other contaminants.
The post-filter, on the other hand, is mostly another 5-micron activated carbon filter that takes up the 5th stage in the RO filtration process and polishes the purified water from the RO storage tank as it’s channeled to the RO faucet.
The water produced by the RO system is highly pure but slightly acidic and as such some RO systems include a 6th stage in the RO filtration process which consist of a remineralization filter that introduces healthy minerals in the water, particularly calcium and magnesium, which as well help balance the pH level of the water and improve its test.
Some RO systems also have a 7th stage filter which is an UltraViolet filter that uses UV rays to destroy any biological contaminants such as harmful bacteria, viruses, fungi, E. coli, and microbes. Each of these filters is inserted into housing where the impurities are left behind in the filter material as the water flows through.
When should you replace the RO filter cartridge?
To ensure the optimal performance of the reverse osmosis system particularly the RO membrane, it is crucial to maintain the filter cartridges and replace them on time.
You should schedule the change on a regular basis because the contaminants from the water can clog the filters within a short time without frequent cleaning. This will affect both the quality of the water and the filtration capacity of the entire system.
Typically, the main RO filter cartridges which consist of the pre-filters should be changed every 6 to 12 months based on how bad the feed water is or how much water you purify. In other words, you change your sediment and carbon filters at least once a year.
If you have an RO system that produces a large amount of pure water, then the cartridges are likely to get saturated by contaminants quickly. They can get exhausted within 3 months, hence you will need to change them more often.
If you continue to use the filters for a prolonged time without changing them on time, then chances of contaminants and other impurities passing into the water you drink are high which in turn can be harmful to your health.
Filter Cartridges Replacement Procedure
Like in the membrane replacement, you need to first shut off the main water supply going into the RO system before starting. Close the ball valve too and turn on the RO faucet to relieve the pressure in the unit. Let the stems to stand for about a minute.
Put a shallow tray right under the filter housing to collect any water that can spill while changing the filters. Now you can start the replacement as follows:
Unscrew the filter housings by twisting and rotating them counterclockwise. Remove the caps and the old filters, for stubborn filter housing use a filter housing wrench.
Make sure to carefully remove the O-rings too without tearing or damaging them. Put them on a clean surface.
Rinse out the filter housings thoroughly with warm water and a bit of liquid soap but make sure all hope is completely rinsed out before placing the new filters.
With a soft clean towel, wipe the O-rings clean and visually inspect them for cracks, tears, and blemishes. A damaged O-ring may not seat properly inside the housing. So, if any of the O-rings appear damaged, then replace it.
Lubricate each of the O-rings slightly using a silicone lubricant and insert them back into their respective housing. Make sure the O-rings are properly seated into their grooved area to provide the watertight seal between the caps and the filter housings.
Now insert the new filter cartridges inside their respective housings and re-inspect the O-rings to ensure proper seating.
Screw back the filter housings to the filter caps, hand tightening only. You should measure the new filters just to be certain they are of proper length and type.
Turn the water supply valve on as well as the RO faucet and let it run while checking for the integrity of the system to ensure there are no leaks.
Let a few gallons of water run through the system and out through the RO faucet while the storage tank is still closed. You should get a steady stream of water which means the new filters are working correctly.
Turn off the faucet and then open the RO storage tank ball valve and let the tank fill completely. Now your system is all set for use.
Popular RO Filter Cartridge Replacement Sets
We also looked at several RO replacement filter cartridges sets on the market and picked some of the best options that are equally worth considering. Below are our reviews of the sets we picked.
Best RO Replacement Filter Cartridges [The Ultimate Reviews]