Reserve is a clear solution of Bromide salts.When initially filling, or refilling a spa, it establishes a bromide reserve, necessary for activating the disinfectant in bromine tablets.
Each bottle contains 32 ounces. 8 oz. will establish proper bromide reserves in a 400 gallon spa, so you should have plenty left over for your next refill.
NOTE: This is not a disinfectant agent, and must be used in conjunction with bromine tablets for proper sanitation of spa water.