The first thing I would do on a refill with hard water is get some kind of filter like this to put on your hose and keep a lot of the hardness out of the water to begin with. If you can get filtered water delivered, that's even better but it's not always available or cheap. I used one of those filters on my last refill and it cut my hardness almost in half from what the tap was (about 400 to 200) and it will make it a lot easier to manage then, especially if you decide to out in a salt water generator because hard water can clog them up fast and cause problems.