A hydrocyclone having a mid-section having a longitudinal axis and a radius, and a fluid injection member releasably connected to the mid-section. The fluid injection member has a dilution passage therethrough and two spaced apart dilution ports, at least one dilution port being at an angle between 15 and 75 degrees relative to the mid-section radius. The injection member comprises a nozzle housing releasably connected to the mid-section, the nozzle housing having a dilution passage therethrough, and a nozzle adapted to be connected to the nozzle housing, the nozzle being planar and having at least one dilution port therethrough, the nozzle being receivable within the dilution passage.