Mr. and Mrs. Z had an older softener that was no longer mechanically functional. After testing the water, it was found that they had sulfur, iron, and hard water. To take care of the rotten egg smell from the sulfur, and the staining from the iron, we recommended the EVFE iron filter. After the filer, is the EVR water softener that will optimize their salt efficency. They now have soft water, no stains and no terrible smell.