diff --git a/src/libs/antares/study/scenario-builder/hydroLevelsData.cpp b/src/libs/antares/study/scenario-builder/hydroLevelsData.cpp
index 4521bf3c1d..93da18dd55 100644
--- a/src/libs/antares/study/scenario-builder/hydroLevelsData.cpp
+++ b/src/libs/antares/study/scenario-builder/hydroLevelsData.cpp
@@ -28,6 +28,7 @@
 #include <sstream>
 #include <iomanip>
 #include "hydroLevelsData.h"
+#include "scBuilderUtils.h"
 
 namespace Antares
 {
@@ -43,7 +44,7 @@ namespace ScenarioBuilder
 		const uint nbYears = study.parameters.nbYears;
 
 		pHydroLevelsRules.reset(study.areas.size(), nbYears);
-		pHydroLevelsRules.fill(-1.);
+		pHydroLevelsRules.fill(std::nan(""));
 
 		return true;
 	}
@@ -70,7 +71,7 @@ namespace ScenarioBuilder
 			{
 				const MatrixType::Type  value = col[y];
 				// Equals to zero means 'auto', which is the default mode
-				if (value < 0.)
+				if (std::isnan(value))
 					continue;
 				assert(index < study.areas.size());
 				value_into_string << value;
diff --git a/src/libs/antares/study/scenario-builder/scBuilderUtils.cpp b/src/libs/antares/study/scenario-builder/scBuilderUtils.cpp
index eadd53dc7d..44a2781fb9 100644
--- a/src/libs/antares/study/scenario-builder/scBuilderUtils.cpp
+++ b/src/libs/antares/study/scenario-builder/scBuilderUtils.cpp
@@ -59,11 +59,11 @@ namespace ScenarioBuilder
 		}
 		catch (std::invalid_argument&)
 		{
-			return -1.;
+			return std::nan("");
 		}
 
 		if (result_tmp < 0.)
-			result = -1.;
+			result = 0.;
 		else
 		{
 			if (result_tmp > maxLevel)
diff --git a/src/libs/antares/study/scenario-builder/scBuilderUtils.h b/src/libs/antares/study/scenario-builder/scBuilderUtils.h
index 2872660ab7..75150f44f3 100644
--- a/src/libs/antares/study/scenario-builder/scBuilderUtils.h
+++ b/src/libs/antares/study/scenario-builder/scBuilderUtils.h
@@ -39,7 +39,6 @@ namespace Data
 {
 namespace ScenarioBuilder
 {
-
 	string fromHydroLevelToString(double d);
 	double fromStringToHydroLevel(const Yuni::String& value, const double maxLevel);
 
diff --git a/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.cpp b/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.cpp
index 1a8c5e2e4f..80de6a4ca7 100644
--- a/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.cpp
+++ b/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.cpp
@@ -47,7 +47,7 @@ namespace Renderer
 	{
 		const double d = cellNumericValue(x, y);
 
-		return (d < 0.)
+		return (std::isnan(d))
 			? wxString() << wxT("rand")
 			: wxString() << fromHydroLevelToString(d);
 	}
@@ -82,6 +82,14 @@ namespace Renderer
 		return 0.;
 	}
 
+	IRenderer::CellStyle hydroLevelsScBuilderRenderer::cellStyle(int x, int y) const
+	{
+		bool valid = (!(!study) && !(!pRules) && std::isnan(cellNumericValue(x, y)));
+		return (valid)
+			? cellStyleDefaultCenterDisabled
+			: cellStyleDefaultCenter;
+	}
+
 } // namespace Renderer
 } // namespace Datagrid
 } // namespace Component
diff --git a/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.h b/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.h
index 09b4d91d49..cff2807936 100644
--- a/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.h
+++ b/src/ui/simulator/toolbox/components/datagrid/renderer/scenario-builder-hydro-levels-renderer.h
@@ -46,6 +46,7 @@ namespace Renderer
 		wxString cellValue(int x, int y) const;
 		bool cellValue(int x, int y, const Yuni::String& value);
 		double cellNumericValue(int x, int y) const;
+		IRenderer::CellStyle cellStyle(int x, int y) const;
 	}; // class hydroLevelsScBuilderRenderer