Like most RO systems, the ROES-PH75 uses a set of three pre-filters to remove impurities that might clog or damage the RO membrane.
This improves filtration performance and extends the lifespan of the semi-permeable membrane.
First up is a 5-micron sediment filter.
It’s made from polypropylene microfibers that trap silt, sand, rust, and dust particles as water passes through. The cartridge is 10” long, which allows it to hold a lot of dirt before you need to replace it.
Unlike the RO membrane, which is sensitive to certain chemicals, the sediment filter can withstand exposure to most chemicals and contaminants in water like chlorine.
The second pre-filter is a 10-micron carbon block filter.
It filters out organic chemicals like chlorine, chloramine, VOCs, and pesticides by trapping their molecules within the porous carbon structure.
In addition to chemicals, it traps ultra-fine sediment that may have passed through the sediment filter.
Carbon block filters are generally better than GAC (granular activated carbon) filters.
Because the filter is one uniform block, rather than separate granules, it filters water more effectively and releases few or no carbon fines into the water.
The third pre-filter is also a 10-micron carbon block filter.
Having double carbon block filters significantly increases filtration performance and extends the life of individual filters.