In an embodiment, a polymerization process comprises circulating, with a pump, a reaction mixture slurry in a polymerization loop reactor during a polymerization process, detecting a pressure change in the reaction mixture slurry downstream of the pump, generating, by a pressure controller, a takeoff valve actuation signal for a takeoff valve based on the pressure change, generating, by the pressure controller, a correction to the takeoff valve actuation signal, generating, by the pressure controller, a time delay for the correction, applying the correction to the takeoff valve actuation signal to generate a corrected takeoff valve actuation signal, providing the corrected takeoff valve actuation signal to the takeoff valve after the time delay, and adjusting a position of the takeoff valve in response to providing the corrected takeoff valve actuation signal. The reactor pressure is based on the takeoff valve position.