A memory controller includes an interface and a processor. The interface communicates with a plurality of memory cells. The processor produces one or more readouts by reading a group of the memory cells using one or more Read Voltages (RVs). Based on the readouts, the processor calculates for a given RV among the RVs a sample of an error signal indicative of a deviation between the given RV and an optimal RV that results in a minimal number of errors in reading the memory cells in the group. The processor applies a filter to the sample of the error signal so as to produce an updated value of the given RV, the filter includes one or more filter taps storing data related to previous samples of the error signal, and reads a second group of the memory cells using the updated value of the given RV.