I used one of those mineral cartridges-a "frog" or whatever they're called, to cut back on bromine use.
The best thing I've had, though, was an Ecosmarte -
https://www.ecosmarte.com/pool-spa - used on a swimspa. Not cheap, the spa system is 1600, but no odor or chemicals at all. It uses ti and copper plates and an electric current to generate sanitizing copper ions. You do have to keep acidity in line for it to work, but easy and worth it. Only negative is that it can turn bleached blond hair green, reversible with lemon juice.