Spa Choice Bromine Booster establishes a bromine reserve in freshly filled hot tub spa water. An amplifier that increases the sanitizing power of the bromine. For use with a freshly-filled spa; place Bromine tabs in the chemical feeder then add 2 ounces of Bromine Booster directly to the water. Allow the spa to circulate until a bromine reading of 3-5 ppm is attained and do not use your spa until then. You may have to adjust the feeder to maintain this level of bromine. Check the bromine levels before each use to ensure a proper reading; you may have to adjust the feeder to maintain the proper level and check the feeder regularly to make sure there are enough tablets in it. Note: Spa Sauna Direct only ships pool and spa chemicals within the continental United States.