Our new pool under construction has an auto fill system. However, the local water co receives most of its water from canals/etc that cross great distances and pick up calcium and other minerals along the way. End result is that the default hardness of any water entering the pool would be extremely high (up to roughly 300ppm, or ~17 grains per gallon). To avoid a long term maintenance nightmare, especially with regard to cleaning the salt water system cells, I'd like to put something in to reduce the hardness before it enters the pool. My pool builder has told me we need to avoid a general water softener as that might be detrimental to our pebble sheen. Is there a standard solution out there for this? Something that would be easy to maintain and that we can use w/ reasonable cost over the 30 year lifetime that we expect to own and operate this pool?