For many years I have been using an under sink filter to provide softened water for boiling to prevent limescale in kettles etc. Does anyone know what the resin granules are, as I would like to buy in bulk to reduce costs. Research indicates that they are called ion-exchange resin, but there appear to be several different types. Can anyone help with this identification.
TIA
They're polyester resin with some sort of reactive coating. I don't know any more than that, but there are lots of different kinds. Just get water softener resin from a softener manufacturer. I'd forget buying in bulk, unless you want a pallet load from the manufacturers. They used to use sodium zeolyte, a mineral with a microscopic honeycomb crystalline structure.
Info here;
http://www.purolite.com/RelId/60634...tes_WaterSofteningBasics_9_20_07_JS BLEND.pdf
I think you should do some reading about this. Softened water is not the same as naturally soft water you'd get from rainwater or in areas with no chalk or limestone bedrock. In softened water, the calcium carbonates are changed into sodium carbonates. Calcium salts are beneficial, sodium salts are not; I wouldn't drink it. A filter won't remove dissolved solids.
The sodium salts are much more soluble in water and stay in solution, rather than precipitating when heated. You'd probably be better with an undersink reverse osmosis machine, which removes most of the dissolved solids.