Cleaning glass and dishwashers

I missed most of a recent thread about running glassware through dishwashers and subsequent etching/streaking. We ruined a decent set of glassware over the years; we ran the pieces through our dishwasher and all of them ended up etched pretty badly. I found an article in a rather unscientific place (Mr. Fixit maybe?) that seemed to make sense to this rather un-chemically-inclined dude. Most dishwasher soaps have some amount of phosphates in them -- used primarily to soften the water. However, if you already use softened water (like we do for all of our hot water), then the phosphates in the soap will cause the etching. The article didn't go into specifics as to how/why. Soooo, we purchased a new set of glassware and changed dishwashing soap to a phosphate-free brand -- Seventh Generation -- and behold! No etching. Do the chemically-inclined dudes in the MhBA world have ideas about this? R -- Russ Loucks mailto: rjl(a)mm.com office: (952) 842-5358 mobile: (612) 387-4108