New tub...new owner, I would say dump the water, keep your filters, and start over. Chalk it up to something new. What are you testing your water with, strips or test kit? If you are using test strips, your readings may be way off, and you don't know it. I had similar problems when I started my tub about a year and a half ago. The test strips were way off and I probably went overboard with the chems the first couple of months. Get a Taylor Kit for accurate results. I use Bromine and finally feel that I have it down right. I use whatever test strips I have left only on occasion. If the Bromine is used correctly, you will have no or a very little bromine smell. Good luck!