The Zigman
03-06-2010, 2:05 PM
I am postring this here because more people in SW use RO/DI than in FW.
I am curious if DI will remove the Ions left behind by a water softener.
Anyone Know?
Thanks
fsn77
03-08-2010, 10:02 AM
Yes, DI resin will remove what a water softener puts into the water. If you're using a RO/DI unit, the RO membrane should remove some of it and the DI will just pull out the rest. If you're using just DI, you'll likely exhaust the resin quickly. Checking the TDS (total dissolved solids) will provide a better idea on how much the water softener is adding if you check the water before the softener and then after it. It may be better to install a RO/DI unit so that it is supplied by water before it goes through a water softener.
Amphiprion
03-08-2010, 12:26 PM
All the water softener is doing is adding sodium and/or potassium ions in place of calcium and magnesium. An RO membrane will readily remove these to about 95%, which, as fsn77 said, will keep from exhausting your DI resin. The DI resins work a bit differently from the softening resin, in that they add hydrogen and hydroxide ions, which make a net exchange of water molecules and, therefore, pure(er) water.