I live in Scottsdale, AZ where the hardness of tap water is 250. When I filled my pool in June and started testing with a Taylor kit, my CH was 350. Naturally it has crept up as the warm summer has evaporated the pool water. It is now 450. I have already started seeing calcium deposits on the spa spillover. I know I could drain the pool by half and refill with tap water, but it wouldn't be long before I'd be in the same boat again, and it costs over $250 in water to do it. I have read about reverse osmosis trucks that can remove hardness, but I imagine this is even more expensive than refilling the pool. What would the experts suggest? I can certainly keep my pH low enough for my CSI to be in range. I expect my CH will be over 500 very soon. Another thought I had was to install a home water softener, but they'd have to do it in a way that my automatic pool refill tap was included.