Assuming your pool is an inground, you definitely need to make sure you maintain your calcium hardness, unless you have fiberglass, or vinyl. Though you will probably only be topping off your water, you will add very little salt to the pool water, of course this depends on what type of softener you have and how hard your raw/municipal water is. I have put quite a few systems (whole house) in that have pools, and have never seen any adverse effects, either way, most people like the fact the water feels better, over time as the water is replaced. Let me know if you have any questions, knowing what type of softener you have, I can likely tell you exactly how much salt you will add per 100 gal.