diff --git a/pywr-schema/src/nodes/core.rs b/pywr-schema/src/nodes/core.rs
index 94719fa5..cb2f8f0c 100644
--- a/pywr-schema/src/nodes/core.rs
+++ b/pywr-schema/src/nodes/core.rs
@@ -831,7 +831,7 @@ pub struct AggregatedStorageNode {
 }
 
 impl AggregatedStorageNode {
-    const DEFAULT_ATTRIBUTE: NodeAttribute = NodeAttribute::Outflow;
+    const DEFAULT_ATTRIBUTE: NodeAttribute = NodeAttribute::Volume;
 
     pub fn input_connectors(&self) -> Vec<(&str, Option<String>)> {
         // Not connectable