Hi. I am in the process of installing an auto fill in my new/old pool. I can plumb the auto fill either with hard water (15 - 17.5 grains/gal; 250 - 300 ppm) or softened water (or I suppose I could even blend it). One thought was to initially fill with hard and get the calcium levels right, and autofill with the softened water thereafter holding the calcium level in the pool constant. I live in Phoenix so there will be significant evaporation. I am about to have the pool resurfaced, likely pebble shean and am considering a SWCG system (27K gal so thinking 40k sizing on SWCG). Any thoughts would be appreciated. Thanks!