Bromine generators work the same way that chlorine generators do, that is they convert bromide ions into bromine which then quickly forms the killing form of bromine called hypobromous acid or HOBr (like HOCl).
You add bromide ions to the pool by adding a bromide salt called sodium bromide (NaBr, like NaCl). You need somewhere around 1100 to 1500 ppm of bromide in the water for most electrolysis devices to make bromine.
After that, you have a bromine pool or spa. As with any bromine treated water system, there are a few characteristics you will have to deal with or be aware of.
First is that bromine does not do it all. Bromine will indeed kill bacteria, algae and other organisms. It will also do a good job of destroying ammonia.
Bromine is rather poor at destroying nitrogen-containing compounds which are called N-bromo compounds and at destroying organic material and swimmer waste such as oil, saliva, sweat, urine, feces, etc. which are sometimes referred to as or