diff --git a/firmware/sampling.cpp b/firmware/sampling.cpp
index 1e3dc84..577a859 100644
--- a/firmware/sampling.cpp
+++ b/firmware/sampling.cpp
@@ -41,9 +41,13 @@ static void SamplingThread(void*)
         float r2_opposite_phase = (r_1 + r_3) / 2;
 
         // Compute AC (difference) and DC (average) components
-        nernstAc = f_abs(r2_opposite_phase - r_2);
+        float nernstAcLocal = f_abs(r2_opposite_phase - r_2);
         nernstDc = (r2_opposite_phase + r_2) / 2;
 
+        nernstAc =
+            (1 - ESR_SENSE_ALPHA) * nernstAc +
+            ESR_SENSE_ALPHA * nernstAcLocal;
+
         // Exponential moving average (aka first order lpf)
         pumpCurrentSenseVoltage =
             (1 - PUMP_FILTER_ALPHA) * pumpCurrentSenseVoltage +
diff --git a/firmware/wideband_config.h b/firmware/wideband_config.h
index cfb87b6..5aa58cf 100644
--- a/firmware/wideband_config.h
+++ b/firmware/wideband_config.h
@@ -15,6 +15,9 @@
 #define ESR_SUPPLY_R (22000)
 #define VM_RESISTOR_VALUE (10)
 
+// Heater low pass filter
+#define ESR_SENSE_ALPHA (0.002f)
+
 // *******************************
 //       Pump current sense
 // *******************************
@@ -25,8 +28,8 @@
 #define LSU_SENSE_R (61.9f)
 
 // Pump low pass filter alpha
-// sampling at 2.5khz, alpha of 0.1 gives about 42hz bandwidth
-#define PUMP_FILTER_ALPHA (0.1f)
+// sampling at 2.5khz, alpha of 0.01 gives about 50hz bandwidth
+#define PUMP_FILTER_ALPHA (0.02f)
 
 // *******************************
 //        Pump controller