diff --git a/monitoring/kps-values-k3s.yaml b/monitoring/kps-values-k3s.yaml
index 1307513..9c8b7f4 100644
--- a/monitoring/kps-values-k3s.yaml
+++ b/monitoring/kps-values-k3s.yaml
@@ -29,7 +29,7 @@ alertmanager:
           resources:
             requests:
               storage: 5Gi
-          storageClassName: local-path
+          storageClassName: merlin-local-iscsi-alertmanager
 
 grafana:
   enabled: true
@@ -48,6 +48,8 @@ grafana:
     - ReadWriteOnce
     enabled: true
     size: 10Gi
+    # StatefulSet VolumeClaimTemplate is immutable; must stay "local-path" to match the
+    # existing StatefulSet spec. Actual PVC binds to merlin-local-iscsi-grafana PV.
     storageClassName: local-path
     type: sts
 
@@ -123,7 +125,7 @@ prometheus:
           resources:
             requests:
               storage: 30Gi
-          storageClassName: local-path
+          storageClassName: merlin-local-iscsi-prometheus
 
 prometheus-node-exporter:
   affinity: