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When comparing water filtration systems, reverse osmosis systems usually come with 5 filter stages.
What sets a 6-stage system apart is the inclusion of a unique filter stage, often dedicated to remineralization or UV treatment (or both).
So, is a 6th and potentially more expensive stage needed? Let’s see.
First of all, what’s the difference between a 5-stage versus a 6-stage reverse osmosis system?
Well, 6-stage reverse osmosis systems are pretty similar in their configuration to 5-stage RO systems, but a 6-stage is likely to have an extra ‘special’ type of filter. This could be a UV filter or a remineralization filter.
Several combinations of filter stages are available in a 5-stage RO system for water purification. These include the following setups:
To illustrate, a typical setup would involve the following stages:
6-stage reverse osmosis systems are comparable 5-stage setups in terms of the various filter types that can be utilized. There are numerous setup possibilities.
Alternatively, a combination of one sediment filter and one carbon pre-filter, along with the RO membrane, a carbon post-filter, a remineralization filter, and a UV filter can be employed. The choice of setup depends on individual requirements and preferences.
All the stages within a reverse osmosis system are designed for specific contaminants and work synergistically together.
Sediment filtration is a critical step in water purification, as it effectively eliminates debris from the water. Positioned at the start of the filtration process, it captures larger particles, enabling the subsequent stages to target other contaminants without getting clogged.
During the carbon filtration stage, water passes through activated carbon in granular or block form, eliminating tastes, odors, cloudiness, colors, and all kinds of chemicals.
As a result, any residual chlorine taste, often present in municipal water, is eliminated.
During this critical phase, water passes through a semipermeable membrane with ultra-small pores measuring 0.0001 microns. A remarkable 99% of impurities, including the particularly nasty ones like lead and nitrates, are eliminated from the water.
After undergoing reverse osmosis, water is often perc sitting in a storage tank. Incorporating a coconut shell carbon post-filter eliminates any lingering taste once the water leaves said tank.
An ultraviolet (UV) purifier is an optional component that can be added to a 6-step RO system. It proves beneficial when the feed water contains microorganisms, such as bacteria or cysts. This purification stage utilizes ultraviolet light to kill pathogens in the water, preventing their reproduction.
A remineralization filter is an additional filtration stage that can be added, replenishing the water with essential minerals such as calcium and magnesium for taste and health. This imparts a subtly mineralized flavor to the water, along with an increase in pH level.
So which is better, a 5-stage or a 6-stage reverse osmosis system?
Well, it depends. Not every 5 stage and 6-stage reverse osmosis setup is the same. So the question really is, what filter stages are being used?
If your water is contaminated with microorganisms, plus you prefer remineralizing your RO water before consumption, then the right 5-stage or 6-stage RO system can both work.
Manufacturers often add extra filter stages to their systems for no reason except marketing and upselling. The number of steps alone doesn’t determine filtration system performance. While more stages can potentially improve contaminant reduction, repeating the same filter media consecutively may not enhance filtration efficiency. You have to look at the contaminants in your water and then determine if you need an extra step or two in your system.
Some things to consider when determining how many stages in your RO system and what configuration include:
Assess specific needs by testing water and determining the necessary stages, such as employing UV filters for bacteria elimination or adding sediment filtration for heavy sediment.
If you just want to get rid of the taste of chlorine, a carbon filter might be enough. To have pure water with minerals added back for taste, consider a system with a remineralization filter.
Make sure to clearly understand what you want before starting your shopping journey so you aren’t unnecessarily upsold.
Installing a larger system with multiple stages can become increasingly challenging. While a 3-stage system can be easily installed at home, a 10-stage system may pose difficulties, mainly if space is limited.
The maintenance level of an RO system usually depends on the number of filtration steps, although there are exceptions. Multi-stage systems with multiple filter materials in one cartridge are easier to install and require less frequent maintenance. Typically, the system becomes pricier with each additional filtration step. This applies not only to the initial purchase but also to the annual running costs when accounting for filter replacements.
If you have any questions about 5 vs 6-stage reverse osmosis please don’t hesitate to leave a comment below!
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