I bought my spa used and have no idea if the previous owners used chlorine or bromine.
I have filled the tub once for troubleshooting flow and heat problems and now it is drained while I replace the parts.
I want to use bromine in this tub but I do not know if it will cause problems if the previous owners used chlorine.
Any advice will be appreciated.
Thanks..

Changing from chlorine or bromine is not a issue, changing from chlorine or bromine to baquacil is. If you are starting with a fresh re-fill just get some bromine starter to jump start your bromine levels, the floater won't release bromine fast enough to keep your levels proper.

Thanks Jeffz ,
I had already bought the bromine starter and the floater as well but didnt want to treat it until I got advice. I am a newbie to spas so I didnt want to take a risk of tearing up something.
Thanks again for the input.

I'm curious why you want to use bromine. Have you thought about using a metal ion sanitizer, such as the Nature 2 silver ion product, together with a dichlor shock product like Spa Essentials Shock Xtra? Using a mineral ion product that is in a device that stays in the tub filter well or filter is supposed to allow keeping the dichlor to a minimum (one or two capfulls a week, depending on tub activity). I have been using this approach and I don't really smell chlorine in the tub. This is all I need to use, according to my spa dealer.

honestly I know nothing about the ionizers . This is my first spa and therefore ,I am spa stupid

Just a side note:

Every manufacturer (Baquaspa, Nature 2, etc.) thinks they are the biggest and best thing since sliced bread (which came about after the toaster, in case you ever wondered). Personally, I stick with chlorine. Bar none, it is the best sanitizer out there in regards to it's purifing ability. Sure, it does smell the strongest of any out there, but when properly maintained, the smell is minimal. Most of the time it is the Chlorimines (used chlorine) that you smell, and these are "burned off" by shocking the water once in a while. Consider this, all USDA and FDA regulated production facilities use chlorine for sanitization of the facility.

I would rate Bromine as second best, and I would put the mineral sanitizers at the bottom. I would definentally suppliment mineral sanitizers with Ozone.

I couldn't agree more.
Chemically speaking, it's become marketing side show. What many dealers are pushing now is nealry criminal....

Chlorine, more specifically, sodium dichlor chlorine, is what I reccomend to all my customers... Since it's so inexpensive, dealers don't push it nearly as hard.

Chlorine comes in many forms...
Sodium dichlor type chlorine is what you want (granulated, 55-65% "free" or "availbale" chlorine) Avoid any tablet or liquids...

It's nearly PH neutral, so one you have initially balanced your PH and Alkalinity, they will remain balanced.

Knightstorms, add 1 teaspoon each use (add after getting out) additionally, add 3-4 teaspoons once a week to "shock" the spa. As charger mentioned, this will break down the used up chlorine, called chloromines...

When used in this fashion, you will not smell any chlorine (in fact, chlorine levels will be about the same as your drinking water)

I don't like bromine... PH is way too low.. never enough sanitizer when you need it, and too much when you don't. Eats heaters for breakfast.... However, my customers who routinley use bromine are putting my kids through college, so I probably shouldn't complain

My ph was a little on the high side when I filled the tub with "city water". After shocking the tub and then using the bromine I have noticed the ph tends to be on the low side.
I also noticed that hot springs does not recommend bromine so after hearing it from two experts it is certainly time to drain and refill.
Chlorine it is !!

If you have used any type of chemical feeder in the tub, using bromine, and plan on re-using it for chlorine, I would recommend you get a new one. Also, any equipment that you had bromine in should be disposed of as well, and new purchased for chlorine. The reason behind this is bromine and chlorine can react violently with eachother. You really don't want to have any unnecessary problems when doing the switch. If in doubt, replace.

yea, I know that if you rinse well enough it should be ok, but I wouldn't risk it.

What I recommend to anyone switching from one to the other, is to drain the tub, refill it with clear water, add nothing, and run the spa on heat for 1/2 hour, and high jet for 1/2 hour, and drain and refill again before adding the other chemical. Probably unnecessary, but I feel better about it.

I do have a floating bromine feeder but it is a non refillable type. Other than that , there are no other items I have used in the spa at all.
Does the chlorine in my treated city water react with the bromine?