diff --git a/firmware/sampling.cpp b/firmware/sampling.cpp
index 7f4703c..83755f2 100644
--- a/firmware/sampling.cpp
+++ b/firmware/sampling.cpp
@@ -43,7 +43,10 @@ static void SamplingThread(void*)
         nernstAc = f_abs(r2_opposite_phase - r_2);
         nernstDc = (r2_opposite_phase + r_2) / 2;
 
-        pumpCurrentSenseVoltage = 0.7f * pumpCurrentSenseVoltage + 0.3f * (result.PumpCurrentVoltage - result.VirtualGroundVoltageInt);
+        // Exponential moving average (aka first order lpf)
+        pumpCurrentSenseVoltage =
+            (1 - PUMP_FILTER_ALPHA) * pumpCurrentSenseVoltage +
+            PUMP_FILTER_ALPHA * (result.PumpCurrentVoltage - result.VirtualGroundVoltageInt);
 
         // Shift history over by one
         r_3 = r_2;
diff --git a/firmware/wideband_config.h b/firmware/wideband_config.h
index e75a3f0..f8ae900 100644
--- a/firmware/wideband_config.h
+++ b/firmware/wideband_config.h
@@ -23,6 +23,10 @@
 // LSU sense resistor - 61.9 ohms
 #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)
+
 // *******************************
 //        Pump controller
 // *******************************