We just got a new Jacuzzi brand hot tub. We've been following the instructions for chemicals as best we can. Every time we finish using it (daily lately) we test and the bromine is zero or close to it. We add more. We test 20 mins later and it's fine. Sometimes even a bit high. However, the next day, its back to zero. Anyone have any ideas or suggestions? Is it safe for us to use when it's at zero?

Thanks!
Yes it's covered when not in use.