diff --git a/Sources/PressureEstimationsFeature/PressureEstimations.swift b/Sources/PressureEstimationsFeature/PressureEstimations.swift
index 6035480..8bef696 100644
--- a/Sources/PressureEstimationsFeature/PressureEstimations.swift
+++ b/Sources/PressureEstimationsFeature/PressureEstimations.swift
@@ -108,11 +108,11 @@ public struct PressureEstimationsView: View {
   }
   
   public var body: some View {
-    ScrollView {
+//    ScrollView {
       EquipmentSettingsFormView(
         store: store.scope(state: \.equipmentSettings, action: \.equipmentSettings)
       )
-    }
+//    }
     .navigationTitle("Equipment Settings")
     .toolbar {
       NextButton { send(.nextButtonTapped) }
@@ -125,10 +125,10 @@ public struct PressureEstimationsView: View {
         action: \.destination.equipmentMeasurements
       )
     ) { measurementStore in
-      ScrollView {
+//      ScrollView {
         EquipmentMeasurementFormView(store: measurementStore)
           .navigationTitle("Existing Measurements")
-      }
+//      }
     }
   }
 }
diff --git a/Sources/SharedModels/EquipmentMeasurement.swift b/Sources/SharedModels/EquipmentMeasurement.swift
index 08045e7..dab6874 100644
--- a/Sources/SharedModels/EquipmentMeasurement.swift
+++ b/Sources/SharedModels/EquipmentMeasurement.swift
@@ -85,13 +85,15 @@ public enum EquipmentMeasurement: Equatable, Sendable {
     }
 
     public var externalStaticPressure: Positive<Double> {
-      var postFilterAdder = Positive<Double>.zero
-      if $postFilterPressure > $manufacturersIncludedFilterPressureDrop {
-        postFilterAdder = $postFilterPressure - $manufacturersIncludedFilterPressureDrop
+      guard $manufacturersIncludedFilterPressureDrop == .zero else {
+        return Positive(
+          ($postFilterPressure.positiveValue - $manufacturersIncludedFilterPressureDrop.positiveValue)
+          + $supplyPlenumPressure.positiveValue
+        )
       }
-      return $returnPlenumPressure
-      + postFilterAdder
-      + $supplyPlenumPressure
+      return Positive(
+        $returnPlenumPressure.positiveValue + $supplyPlenumPressure.positiveValue
+      )
     }
   }
   
@@ -112,7 +114,6 @@ public enum EquipmentMeasurement: Equatable, Sendable {
     }
   }
 
-  // TODO: Needs updated for when forms are using `minmal` values.
   public struct FlaggedMeasurement: Equatable, Sendable {
     public var airflow: Flagged
     public var coilPressureDrop: Flagged
@@ -287,7 +288,11 @@ public enum EquipmentMeasurement: Equatable, Sendable {
     }
 
     public var externalStaticPressure: Positive<Double> {
-      ($postFilterPressure - $manufacturersIncludedFilterPressureDrop) + $preCoilPressure
+      let double = ($postFilterPressure.positiveValue - $manufacturersIncludedFilterPressureDrop.positiveValue)
+      + $preCoilPressure.positiveValue
+      
+//      ($postFilterPressure - $manufacturersIncludedFilterPressureDrop) + $preCoilPressure
+      return Positive(double)
     }
   }
 }
diff --git a/Tests/EstimatedPressureTests/EstimatedPressureTests.swift b/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
index 5f7b173..e494aa0 100644
--- a/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
+++ b/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
@@ -65,7 +65,38 @@ final class PositiveNumericTests: XCTestCase {
     )
 
     sut = envelope.externalStaticPressure.positiveValue
-    XCTAssertEqual(round(sut * 10) / 10, 0.7)
+    XCTAssertEqual(round(sut * 10) / 10, 0.5)
+
+  }
+  
+  func testExternalStaticPressureWithManufacturersFilterDrop() {
+    var envelope = EquipmentMeasurement.furnaceAndCoil(
+      .init(
+        airflow: 1200,
+        manufacturersIncludedFilterPressureDrop: 0.1,
+        returnPlenumPressure: -0.1,
+        postFilterPressure: -0.2, // here to test it makes positive.
+        preCoilPressure: 0.4,
+        supplyPlenumPressure: 0.1
+      )
+    )
+
+    var sut = envelope.externalStaticPressure.positiveValue
+    XCTAssertEqual(round(sut * 10) / 10, 0.5)
+
+
+    envelope = .airHandler(
+      .init(
+        airflow: 1200,
+        manufacturersIncludedFilterPressureDrop: 0.1,
+        returnPlenumPressure: -0.2,
+        postFilterPressure: 0.3,
+        postCoilPressure: 0.5,
+        supplyPlenumPressure: 0.3)
+    )
+
+    sut = envelope.externalStaticPressure.positiveValue
+    XCTAssertEqual(round(sut * 10) / 10, 0.5)
 
   }