diff --git a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.cpp b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.cpp
index 97584c917ed51bed3299e3653e49b268a9dfb5d1..682f8e9d68a052e9bf30e8314487b8c6cb433e1e 100644
--- a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.cpp
+++ b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.cpp
@@ -62,14 +62,17 @@ PolarizationCorrections ExperimentPresenter::polarizationCorrectionsFromView() {
   return PolarizationCorrections(cRho, cAlpha, cAp, cPp);
 }
 
-RangeInLambda ExperimentPresenter::transmissionRunRangeFromView() {
+boost::optional<RangeInLambda>
+ExperimentPresenter::transmissionRunRangeFromView() {
   auto const range = RangeInLambda(m_view->getTransmissionStartOverlap(),
                                    m_view->getTransmissionEndOverlap());
-  if (range.isValid())
+  if (range.isValid()) {
     m_view->showTransmissionRangeValid();
-  else
-    m_view->showTransmissionRangeInvalid();
-  return range;
+    return range;
+  }
+
+  m_view->showTransmissionRangeInvalid();
+  return boost::none;
 }
 
 std::map<std::string, std::string>
diff --git a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.h b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.h
index b164fb94ec56fc23bb3c411b1502b56e5ae396da..f7712b8e7902936a44f6da8642856e4214a89eaf 100644
--- a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.h
+++ b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenter.h
@@ -79,7 +79,7 @@ public:
 private:
   ExperimentValidationResult validateExperimentFromView();
   PolarizationCorrections polarizationCorrectionsFromView();
-  RangeInLambda transmissionRunRangeFromView();
+  boost::optional<RangeInLambda> transmissionRunRangeFromView();
   std::map<std::string, std::string> stitchParametersFromView();
 
   ExperimentValidationResult updateModelFromView();
diff --git a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenterFactory.h b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenterFactory.h
index 3ab051585f36aa762fa72f6d5126768529eea5ad..8ee7c1e1ed1ff8486b2d012feefcf46f05501c11 100644
--- a/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenterFactory.h
+++ b/qt/scientific_interfaces/ISISReflectometry/GUI/Experiment/ExperimentPresenterFactory.h
@@ -26,15 +26,13 @@ private:
   Experiment makeModel() {
     // TODO get defaults from algorithm
     auto polarizationCorrections = PolarizationCorrections(0.0, 0.0, 0.0, 0.0);
-    auto transmissionRunRange = RangeInLambda(0.0, 0.0);
     auto stitchParameters = std::map<std::string, std::string>();
     auto perThetaDefaults = std::vector<PerThetaDefaults>(
         {PerThetaDefaults(boost::none, std::pair<std::string, std::string>(),
                           boost::none, boost::none, ProcessingInstructions())});
     return Experiment(AnalysisMode::PointDetector, ReductionType::Normal,
                       SummationType::SumInLambda,
-                      std::move(polarizationCorrections),
-                      std::move(transmissionRunRange),
+                      std::move(polarizationCorrections), boost::none,
                       std::move(stitchParameters), std::move(perThetaDefaults));
   }
 };
diff --git a/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.cpp b/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.cpp
index 04ea1cc921b0b27acb7a5448dfa5fe9e7853d858..810caca428cc7131e911f2ab148b644f7e5e1d43 100644
--- a/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.cpp
+++ b/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.cpp
@@ -8,7 +8,7 @@ namespace CustomInterfaces {
 Experiment::Experiment(AnalysisMode analysisMode, ReductionType reductionType,
                        SummationType summationType,
                        PolarizationCorrections polarizationCorrections,
-                       RangeInLambda transmissionRunRange,
+                       boost::optional<RangeInLambda> transmissionRunRange,
                        std::map<std::string, std::string> stitchParameters,
                        std::vector<PerThetaDefaults> perThetaDefaults)
     : m_analysisMode(analysisMode), m_reductionType(reductionType),
@@ -25,9 +25,7 @@ PolarizationCorrections const &Experiment::polarizationCorrections() const {
   return m_polarizationCorrections;
 }
 
-bool Experiment::isValid() const { return m_transmissionRunRange.isValid(); }
-
-RangeInLambda const &Experiment::transmissionRunRange() const {
+boost::optional<RangeInLambda> Experiment::transmissionRunRange() const {
   return m_transmissionRunRange;
 }
 
diff --git a/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.h b/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.h
index 16b969ff2b9d90c32b217a11ee6d9a29544c2c4b..e2a5380ea29fea5030546bc5fc36fc396a0a9607 100644
--- a/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.h
+++ b/qt/scientific_interfaces/ISISReflectometry/Reduction/Experiment.h
@@ -41,16 +41,15 @@ public:
   Experiment(AnalysisMode analysisMode, ReductionType reductionType,
              SummationType summationType,
              PolarizationCorrections polarizationCorrections,
-             RangeInLambda transmissionRunRange,
+             boost::optional<RangeInLambda> transmissionRunRange,
              std::map<std::string, std::string> stitchParameters,
              std::vector<PerThetaDefaults> perThetaDefaults);
 
-  bool isValid() const;
   AnalysisMode analysisMode() const;
   ReductionType reductionType() const;
   SummationType summationType() const;
   PolarizationCorrections const &polarizationCorrections() const;
-  RangeInLambda const &transmissionRunRange() const;
+  boost::optional<RangeInLambda> transmissionRunRange() const;
   std::map<std::string, std::string> stitchParameters() const;
   std::vector<PerThetaDefaults> const &perThetaDefaults() const;
 
@@ -63,7 +62,7 @@ private:
   SummationType m_summationType;
 
   PolarizationCorrections m_polarizationCorrections;
-  RangeInLambda m_transmissionRunRange;
+  boost::optional<RangeInLambda> m_transmissionRunRange;
 
   std::map<std::string, std::string> m_stitchParameters;
   std::vector<PerThetaDefaults> m_perThetaDefaults;