If you live in an area with high calcium water, or just bad water to begin with and you are looking to get your ppm down to a reasonable level. I bring you....
THE MR. CLEAN AUTO DRY CAR WASH. Ok so seriously, you are asking me grave, what the hell does this have to do with me and my hard water. Well I read about this on some other forums and thought I could help a few people out here with it. The starter filter that comes with it does about 30 gallons, and the real filters do about 3 times as much so each filter filters about 100 gallons at the price of 6.50 a filter thats about 6 and a half cent s a gallon for water thats 20 ppm. You can tear apart the actual gun and turn it into a nice wall unit, it's very small and portable. You need a garden hose or garden hose attachment to put it on your sink. Ace is the only local place I found that carries em, but who knows do a lil reasearch and find yourself one, at the price ratio of most 200 dollar R/o units you can get a small home unit for 30 bucks, it takes it about an hour to fill up a 35 gallon rez. If you have any questions lemme know. Obviously you don't use the soap.