Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Service/HeightStructuresCalculationService.cs
===================================================================
diff -u -rf744bb990260662f885d34811a1ea042dae18550 -r5cdaf6a62202805aa0abe5636e372a66b1bec723
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Service/HeightStructuresCalculationService.cs	(.../HeightStructuresCalculationService.cs)	(revision f744bb990260662f885d34811a1ea042dae18550)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Service/HeightStructuresCalculationService.cs	(.../HeightStructuresCalculationService.cs)	(revision 5cdaf6a62202805aa0abe5636e372a66b1bec723)
@@ -77,7 +77,7 @@
                 calculation.Name,
                 () =>
                 {
-                    HydraRingCalculationService.PerformCalculation(
+                    HydraRingCalculationService.Instance.PerformCalculation(
                         hlcdDirectory,
                         ringId,
                         HydraRingUncertaintiesType.All,