We have had the Keosan Mineral Water System for 8 years! We are still using it, and we just change the filter tube once a year. So it saves us money.
This filter has 8 stages and it is already good for our tap water which comes from the local water system, which is already filtered. But we want to filter it some more, so we use the Keosan to filter it some more.
The entire system cost us about $40 for the initial purchase, but succeeding purchases of the water filter replacement costs about $20. It just goes to show that the filter is the more expensive part. We also clean the filter every few months because it does not get dirtied easily.
With the Keosan, we get crystal clear water anytime at a very affordable price. We don't have to buy purified water everytime.