diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
index 5476cd1aa..082626c96 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingModel.java
@@ -27,12 +27,22 @@ import java.util.List;
 
 public class BulkUpdatingModel extends AbstractModelDecorator {
     private static final RDFReaderF readerFactory = new RDFReaderFImpl();
-    private Graph graph;
     private AbstractBulkUpdater updater;
 
     protected BulkUpdatingModel(Model m) {
         super(m);
-        graph = m.getGraph();
+        Graph graph = m.getGraph();
+        if (graph instanceof RDFServiceGraph) {
+            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
+        } else if (graph instanceof SparqlGraph) {
+            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        } else {
+            updater  = null;
+        }
+    }
+
+    protected BulkUpdatingModel(Model m, Graph graph) {
+        super(m);
         if (graph instanceof RDFServiceGraph) {
             updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
         } else if (graph instanceof SparqlGraph) {
diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
index c7fe01d98..4fd61c892 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/BulkUpdatingOntModel.java
@@ -24,12 +24,22 @@ import java.util.List;
 
 public class BulkUpdatingOntModel extends AbstractOntModelDecorator {
     private static final RDFReaderF readerFactory = new RDFReaderFImpl();
-    private Graph graph;
     private AbstractBulkUpdater updater;
 
     protected BulkUpdatingOntModel(OntModel m) {
         super(m);
-        graph = m.getGraph();
+        Graph graph = m.getGraph();
+        if (graph instanceof RDFServiceGraph) {
+            updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
+        } else if (graph instanceof SparqlGraph) {
+            updater = new SparqlBulkUpdater((SparqlGraph)graph);
+        } else {
+            updater  = null;
+        }
+    }
+
+    protected BulkUpdatingOntModel(OntModel m, Graph graph) {
+        super(m);
         if (graph instanceof RDFServiceGraph) {
             updater = new RDFServiceBulkUpdater((RDFServiceGraph)graph);
         } else if (graph instanceof SparqlGraph) {
diff --git a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
index df2cff649..b8fccdc1b 100644
--- a/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
+++ b/api/src/main/java/edu/cornell/mannlib/vitro/webapp/rdfservice/adapters/VitroModelFactory.java
@@ -46,7 +46,7 @@ public class VitroModelFactory {
 
 		Model unionModel = ModelFactory.createModelForGraph(unionGraph);
 
-		return new BulkUpdatingModel(unionModel);
+		return new BulkUpdatingModel(unionModel, baseGraph);
 	}
 
 	public static OntModel createUnion(OntModel baseModel, OntModel plusModel) {
@@ -58,7 +58,7 @@ public class VitroModelFactory {
 		Model unionModel = ModelFactory.createModelForGraph(unionGraph);
 		OntModel unionOntModel = ModelFactory.createOntologyModel(OWL_MEM, unionModel);
 
-		return new BulkUpdatingOntModel(unionOntModel);
+		return new BulkUpdatingOntModel(unionOntModel, baseGraph);
 	}
 
 	public static Model createModelForGraph(Graph g) {