RO and RO/DI Systems - How do they work?

Reverse Osmosis (RO) and Reverse Osmosis / Deionization (RO/DI) systems are the most popular filtration systems for purifying water at home. An RO system is great for freshwater aquariums, planted aquariums, drinking water and horticulture. Adding a Deionization stage(s) purifies water even further and is great for saltwater fish and reef aquariums.  

Standard RO Systems have 3 filtration stages while RO/DI systems have 4.  

Stage 1 (Sediment Filter) - the sediment filter is a mechanical filter made of plastic (polypropylene) fibers. Through these densely-packed fibers, any sediment, silt, sand or other particles down to as small as 1 micron are trapped by the filter. The sediment filter protects the other filters from becoming clogged. Stage 2 (Carbon Filter) - the job of the carbon block filter is to remove many of the chemicals and organic pollutants that your RO membrane cannot remove. Some of these chemicals, such as chlorine, can damage your RO membrane quickly. The carbon block filter is made by taking activated carbon granules made from coconut shells and combining it with a binding agent to form a filter sleeve. The carbon has a ton of surface area that works, chemically through adsorption, to bind pollutants.  

Stage 2 (Carbon Filter) - the job of the carbon block filter is to remove many of the chemicals and organic pollutants that your RO membrane cannot remove. Some of these chemicals, such as chlorine, can damage your RO membrane quickly. The carbon block filter is made by taking activated carbon granules made from coconut shells and combining it with a binding agent to form a filter sleeve. The carbon has a ton of surface area that works, chemically through adsorption, to bind pollutants.


Stage 3 (Reverse Osmosis Membranes) - The RO Membrane is the heart of your RO/DI system. Aqua FX RO membranes are made in the USA and remove approximately 95% of impurities from water. The RO Membrane works by using water pressure to separate impurities from purified water. The purified water passes through layers of semi-permeable membrane and is collected through the center channel. This very-thin membrane contains billions of very small pores. Water molecules are able to pass through these pores while contaminates are too large to pass through. The dirty/waste water is separated from the purified water and exits a separate port on your RO system.  


Stage 4 (DI Filter) - the Deionization stage is the final stage of your RO/DI system. It is what purifies your water down to ZERO TDS. A standard Mix-Bed DI Filter contains a mixture of anion and cation DI resin that attracts any remaining impurities coming from the RO filter: leaving you with ultra-pure water.  

Depending on the water parameters, different types of filter cartridges may be used and/or additional filter cartridges may be added. We have numerous options and can customize any system to meet your needs. 

Here at AquaFX, we build all of our RO and RO/DI systems in house. We also use the highest quality components, filter media and resins to ensure that you get the best-performing RO or RO/DI system possible. Better Filters, Better Service!

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