Provided is a method for operating a gas-phase, fluidized-bed reactor. The method has the steps of (a) receiving a signal from a probe in contact with the interior of the reactor or a process component in communication with the reactor, wherein the signal is derived from a physical property or condition within the reactor or the process component; (b) modifying the signal to create a modified signal; and (c) adjusting one or more operating parameters of the reactor in response to the modified signal if the physical property or condition is different than a desired value. There is also a method for reducing fouling in a distributor plate of a gas-phase, fluidized-bed reactor with a recycle line.