Help with high bromine levels

[jpenns]

I recently bought a house with a hot tub, and found some old test strips that were lying around. I was using those and they were showing low bromine levels, so I kept putting more in. Finally I did some reading and realized I needed to shock the water, AND I eventually realized that these old strips were not working properly. After adding shock and using new test strips, my bromine levels are through the roof. To the point where my PH and alkalinity levels, which were previously fine, are not registering the colours in the right spectrum that the labels show. I've read that this is a result of high bromine. The water is a bit low so I've been adding water to get the bromine lower but so far it's still very high. I'm not using the tub because the levels are so off. 

Anyways, now that winter is ending it's time for the water to be dumped and refilled on this bad boy anyways. Should I just do that? The problem is that I live in Canada and it's still fairly cold here. It's still going below freezing at night. Can I safely dump and refill this thing within a day's time? Are there any helpful resources for how to do that?

Thanks for your help.