Question:
I work at Rohm and Haas, and I shouldknow something about ion exchange resins (a little). However, I work ina different area of research (products based on latex polymers), and myexperience with ion exchange resins is not practical (lab mostly). Myquestions mostly come from things people have told me about DI water.Whether they are really true or not, I do not know. So, I am trying toget as much information as I can, and see what makes sense.

I have a few more questions. It seems most people agree that keepingthe outside garden hoses off of the softener is a good thing. Is thisbecause of the effect of DI water on the lawn, or is simply a matter ofnot needing softened water for watering the lawn? If it is the effectof the DI water on the lawn, then why should we not concern ourselveswith the same effects for drinking water? On the other hand, I wasunder the impression that rainwater is pretty soft; so, why worry in thefirst place?

Answer: The difference between DI (deionized) water and soft water is great.Soft water merely exchanges hardness minerals with (usually) sodium.The resulting water has *about* the same dissolved mineral content;the difference being that the *kind* of minerals in the water have nowchanged.

DI water, on the other hand, is much different. Think of it this way:You have two types of resin in the DI unit: cation ion exchangerresin and anion ion exchanger resin. The water passes thru the cationexchanger (this is the part that is most like a traditional "watersoftner"), and then thru the second resin bed, or the anion exchangeresin. The resulting water is, *typically*, very high quality water.When the two resins are regenerated properly, and configures one withthe other in the proper manner, water with less than 0.0001 ppm (partsper million; same as mg/l -- milligrams per liter) mineral content init.

In fact, comparing DI water to distilled water, one finds that DIwater is MUCH higher quality. *Normally*, it would take atriple-pass, quartz still to acheive anywhere near the same qualitythat single-pass DI will.

Also, the cost of DI water is such that watering your lawn with it isnot at all practical. It is great for watering house plants, althocostly. Reverse osmosis water is more than adaquate, in most cases,for house plants.

The high cost of DI is due to the cost and handling requirments of theDIU regenerants. You regenerate with acid and caustic...............rather than s

As the rain falls to the ground, it picks up loads of imputities.Remember when Mercedes had to re-paint all those cars left out in therain? That was due to acid rain; a result of the rain picking up someof the imputities in the air. You can drink it if you want; I figuremy familys' health is worth the 20 cents or so per day I spend on areverse osmosis drinking water system............... Actually, as anowner of a water treatment store, I really don't pay any out-of-pocketmoney for my home RO system

Well for many years the word on the street, or ol' wives tales, was that itwasn't - and there was something to that when the regeneration was done by thehomeowner by adding salt and operating certain valves for a given period oftime to accomplish a 'regeneration'. They were the first softeners and totallymanual. Today although you can get manually regenerated softener/filter valvesthere is no "add your own salt to the resin/media/ tank" types. Plus, there isno proof that softened water is harmful to humans or plumbing, or septicsystems, and the latest studies show that. Additionally, the first 'resin'wasn't resin, it was natural zeolite crystals and needed gobs more salt toregenerate because you needed gobs more zeolite to do the job the new resinsof today do with very little s