A flow battery system includes a first tank having a hydrogen reactant, a second tank having a bromine electrolyte, at least one cell including a hydrogen reactant side operably connected to the first tank through an ¾ feed and return system and a bromine electrolyte side operably connected to the second tank, and a crossover return system. The crossover return system includes a vessel operably connected to the ¾ feed and return system and configured to receive an effluent containing a first portion of the hydrogen reactant and a second portion of the bromine electrolyte, the vessel configured to separate the first portion from the second portion. A first return line returns the first portion of the hydrogen reactant to the first tank and a second return line returns the bromine electrolyte to the second tank.