A process for making a low density polymer in a polymerization reactor system, the process comprising polymerizing an olefin monomer, and optionally an olefin comonomer, in the presence of a diluent in a polymerization reactor to make a polymerization product slurry consisting of a liquid phase and a solid phase, wherein the solid phase comprises an olefin polymer having a density of between about 0.905 g/cm3 to about 0.945 g/cm3; and discharging the polymerization product slurry from the polymerization reactor through a continuous take-off valve to make a mixture further comprising a vapor phase. The mixture comprises a pressure less than a bubble point pressure of a component in the polymerization product slurry.