Reverse osmosis (RO) systems produce two types of treated water and then allow the user to blend them in the final step in the treatment process. One product of the RO system is called ‘bypass water’. This water travels only through the prefilter and then past the activated charcoal. It is therefore free of sediment, organic matter, odour, and chlorine, but it retains the same dissolved mineral content it had before it entered the system.
The other water that comes from an RO system is known as the product water, or permeate. This water has passed through an RO membrane and as a result is ultrapure (at or near 10 ppm). An RO membrane is a filter; the pores in its media are submicron in size,