diff --git a/csharp/App/Backend/DataTypes/Installation.cs b/csharp/App/Backend/DataTypes/Installation.cs
index 3339b0188..893c03364 100644
--- a/csharp/App/Backend/DataTypes/Installation.cs
+++ b/csharp/App/Backend/DataTypes/Installation.cs
@@ -61,8 +61,8 @@ public class Installation : TreeNode
     public string PvStringsPerInverter        { get; set; } = "";
     public string InstallationModel           { get; set; } = "";
     public string ExternalEms                { get; set; } = "No";
-    public string CouplingType               { get; set; } = "DC";
-    public string BackupLoad                 { get; set; } = "None";
+    public string? CouplingType              { get; set; }
+    public string? BackupLoad                { get; set; }
 
     [Ignore]
     public String OrderNumbers  { get; set; }
diff --git a/csharp/App/Backend/Database/Db.cs b/csharp/App/Backend/Database/Db.cs
index e566fc96e..662759edb 100644
--- a/csharp/App/Backend/Database/Db.cs
+++ b/csharp/App/Backend/Database/Db.cs
@@ -294,7 +294,6 @@ public static partial class Db
         fileConnection.Execute("UPDATE Installation SET ExternalEms = 'No' WHERE ExternalEms IS NULL OR ExternalEms = ''");
         fileConnection.Execute("UPDATE Installation SET InstallationModel = '' WHERE InstallationModel IS NULL");
         fileConnection.Execute("UPDATE Installation SET PvStringsPerInverter = '' WHERE PvStringsPerInverter IS NULL");
-        fileConnection.Execute("UPDATE Installation SET BackupLoad = 'None' WHERE BackupLoad IS NULL");
 
         return fileConnection;
         //return CopyDbToMemory(fileConnection);
diff --git a/typescript/frontend-marios2/src/content/dashboards/Information/InformationSodistoreHome.tsx b/typescript/frontend-marios2/src/content/dashboards/Information/InformationSodistoreHome.tsx
index 4884cf972..468e7e512 100644
--- a/typescript/frontend-marios2/src/content/dashboards/Information/InformationSodistoreHome.tsx
+++ b/typescript/frontend-marios2/src/content/dashboards/Information/InformationSodistoreHome.tsx
@@ -376,7 +376,14 @@ function InformationSodistorehome(props: InformationSodistorehomeProps) {
         })
         .catch(() => {});
     }
-    updateInstallation(formValues, props.type);
+    updateInstallation(
+      {
+        ...formValues,
+        couplingType: formValues.couplingType || null,
+        backupLoad: formValues.backupLoad || null
+      },
+      props.type
+    );
   };
 
   const handleDelete = () => {
@@ -912,12 +919,15 @@ function InformationSodistorehome(props: InformationSodistorehomeProps) {
                         </InputLabel>
                         <Select
                           name="couplingType"
-                          value={formValues.couplingType || 'DC'}
+                          value={formValues.couplingType || ''}
                           onChange={handleChange}
                           inputProps={{ readOnly: !canEdit }}
                           displayEmpty
                           notched
                         >
+                          <MenuItem value="">
+                            <em><FormattedMessage id="notSet" defaultMessage="Not set" /></em>
+                          </MenuItem>
                           <MenuItem value="AC">
                             <FormattedMessage id="couplingAC" defaultMessage="AC-coupled" />
                           </MenuItem>
@@ -941,12 +951,15 @@ function InformationSodistorehome(props: InformationSodistorehomeProps) {
                         </InputLabel>
                         <Select
                           name="backupLoad"
-                          value={formValues.backupLoad || 'None'}
+                          value={formValues.backupLoad || ''}
                           onChange={handleChange}
                           inputProps={{ readOnly: !canEdit }}
                           displayEmpty
                           notched
                         >
+                          <MenuItem value="">
+                            <em><FormattedMessage id="notSet" defaultMessage="Not set" /></em>
+                          </MenuItem>
                           <MenuItem value="Whole">
                             <FormattedMessage id="backupWhole" defaultMessage="Whole house" />
                           </MenuItem>
diff --git a/typescript/frontend-marios2/src/interfaces/InstallationTypes.tsx b/typescript/frontend-marios2/src/interfaces/InstallationTypes.tsx
index bdf4c293d..d1adeeb0d 100644
--- a/typescript/frontend-marios2/src/interfaces/InstallationTypes.tsx
+++ b/typescript/frontend-marios2/src/interfaces/InstallationTypes.tsx
@@ -28,8 +28,8 @@ export interface I_Installation extends I_S3Credentials {
   pvStringsPerInverter: string;
   installationModel: string;
   externalEms: string;
-  couplingType: string;
-  backupLoad: string;
+  couplingType: string | null;
+  backupLoad: string | null;
 
   parentId: number;
   s3WriteKey: string;
diff --git a/typescript/frontend-marios2/src/lang/de.json b/typescript/frontend-marios2/src/lang/de.json
index b0348accf..7f91d5bb0 100644
--- a/typescript/frontend-marios2/src/lang/de.json
+++ b/typescript/frontend-marios2/src/lang/de.json
@@ -139,6 +139,7 @@
   "backupWhole": "Komplettes Haus",
   "backupPartial": "Teilnetz",
   "backupNone": "nicht verwendet",
+  "notSet": "Nicht festgelegt",
   "selectModel": "Modell auswählen...",
   "inverterN": "Wechselrichter {n}",
   "clusterN": "Cluster {n}",
diff --git a/typescript/frontend-marios2/src/lang/en.json b/typescript/frontend-marios2/src/lang/en.json
index 2d673d095..39a30399f 100644
--- a/typescript/frontend-marios2/src/lang/en.json
+++ b/typescript/frontend-marios2/src/lang/en.json
@@ -121,6 +121,7 @@
   "backupWhole": "Whole house",
   "backupPartial": "Partial",
   "backupNone": "Not used",
+  "notSet": "Not set",
   "selectModel": "Select model...",
   "inverterN": "Inverter {n}",
   "clusterN": "Cluster {n}",
diff --git a/typescript/frontend-marios2/src/lang/fr.json b/typescript/frontend-marios2/src/lang/fr.json
index 00f690d81..8530516b4 100644
--- a/typescript/frontend-marios2/src/lang/fr.json
+++ b/typescript/frontend-marios2/src/lang/fr.json
@@ -133,6 +133,7 @@
   "backupWhole": "Maison entière",
   "backupPartial": "Partiel",
   "backupNone": "Non utilisé",
+  "notSet": "Non défini",
   "selectModel": "Sélectionner le modèle...",
   "inverterN": "Onduleur {n}",
   "clusterN": "Cluster {n}",
diff --git a/typescript/frontend-marios2/src/lang/it.json b/typescript/frontend-marios2/src/lang/it.json
index 3252aaba7..6e63e18a9 100644
--- a/typescript/frontend-marios2/src/lang/it.json
+++ b/typescript/frontend-marios2/src/lang/it.json
@@ -121,6 +121,7 @@
   "backupWhole": "Intera casa",
   "backupPartial": "Parziale",
   "backupNone": "Non utilizzato",
+  "notSet": "Non impostato",
   "selectModel": "Seleziona modello...",
   "inverterN": "Inverter {n}",
   "clusterN": "Cluster {n}",