Hi Paul,
At first glance water purification can seem confusing and as you would have already read on this forum there is no one right way for everyone. However some simple rules apply.
DI Resin based systems are usually best used in soft water areas. The benefits to using a DI based system are that they never go wrong! you change your resin when the TDS reading goes up and that’s it. Another benefit is that they do not waste any of the input water, so if your on a metered water supply in a soft water area this maybe the way to go. Be aware however, that if you live in a hard water area, you will exhaust your resin very quickly.
R/O systems are best described as liquid separators. They work by separating the free form water molecules from molecules that have bound to or contain dissolved solids. As the R/O units are separators, they have a waste, (or concentrate) output. The amount of waste the R/O unit allows to drain is called the rejection rate and is set by the manufacturer. The simple rule here is that the higher the TDS of your feed water, the higher your rejection rate should be. In a desalination plant where the feed water runs at about 23000 TDS an R/O unit will only recover about 5% of the input water. If your TDS were to read 50ppm your R/O unit could be set at 3 or 4% rejection and will still last many years.
For the most part, most water treatment plants use both R/O and DI technology to ensure water is produced as efficiently as possible.
As a personal recommendation, i would suggest that you spend some time talking with as many suppliers and manufacturers as you can. Most will be happy to help, this will help you with additional considerations, such as fill times and filter replacement schedules etc.
Regards,
Carl,
Clearview Plus Ltd
