diff --git a/Stars Assistant/Services/FleetManager.cs b/Stars Assistant/Services/FleetManager.cs
index 2d364dc..2601593 100644
--- a/Stars Assistant/Services/FleetManager.cs	
+++ b/Stars Assistant/Services/FleetManager.cs	
@@ -21,6 +21,34 @@ public class FleetManager
 
     public FleetManager() {}
 
+    public class FleetSummary
+    {
+        public string Destination { get; set; } = string.Empty;
+        public int TotalIronium { get; set; }
+        public int TotalBoranium { get; set; }
+        public int TotalGermanium { get; set; }
+        public int TotalColonists { get; set; }
+    }
+    private IObservable<IChangeSet<FleetSummary, string>>? _fleetSummaries;
+
+    public void test() 
+    {
+        /*
+        _fleetSummaries = _fleets.Connect()
+            .Group(fleet => fleet.TrueDestination)
+            .Transform(grouping => new FleetSummary
+            {
+                Destination = grouping.Key,
+                TotalIronium = grouping.Items.Sum(f => f.Ironium),
+                TotalBoranium = grouping.Items.Sum(f => f.Boranium),
+                TotalGermanium = grouping.Items.Sum(f => f.Germanium),
+                TotalColonists = grouping.Items.Sum(f => f.Colonists)
+            })
+            .Sort(SortExpressionComparer<FleetSummary>.Ascending(f => f.Planet))
+            .AsObservableChangeSet(summary => summary.Planet);
+        */
+    }
+
     /// <summary>
     /// Load the fleet records from the database and push them into our source cache.
     /// If the data has been freshly imported, call PostProcessImportedData first.
@@ -29,7 +57,12 @@ public class FleetManager
     {
         using var db = Locator.Current.GetService<StarsDatabase>()!;
         var allFleets = db.Fleet.ToList();
-        _fleets.AddOrUpdate(allFleets);
+        _fleets.Edit(innerCache =>
+            {
+                innerCache.Clear();
+                innerCache.AddOrUpdate(allFleets);
+            }
+        );
     }
 
     /// <summary>
diff --git a/Stars Assistant/Services/PlanetManager.cs b/Stars Assistant/Services/PlanetManager.cs
index 1ded2da..19605da 100644
--- a/Stars Assistant/Services/PlanetManager.cs	
+++ b/Stars Assistant/Services/PlanetManager.cs	
@@ -36,6 +36,15 @@ public class PlanetManager
     {
         using var db = Locator.Current.GetService<StarsDatabase>()!;
         var allPlanets = db.Planet.ToList();
-        _planets.AddOrUpdate(allPlanets);
+        var cacheKeys = _planets.Keys.ToList();
+        var planetNames = from p in allPlanets select p.Name;
+        var planetsToDelete = cacheKeys.Except(planetNames);
+        _planets.Edit(innerCache => 
+            {
+                foreach (var name in planetsToDelete)
+                    innerCache.RemoveKey(name);
+                innerCache.AddOrUpdate(allPlanets);
+            }
+        );
     }
 }
diff --git a/Stars Assistant/Stars Assistant.csproj b/Stars Assistant/Stars Assistant.csproj
index 9ceef65..a073113 100644
--- a/Stars Assistant/Stars Assistant.csproj	
+++ b/Stars Assistant/Stars Assistant.csproj	
@@ -18,6 +18,7 @@
   <ItemGroup>
     <PackageReference Include="Avalonia.ReactiveUI" Version="11.1.3" />
     <PackageReference Include="CsvHelper" Version="33.0.1" />
+    <!-- PackageReference Include="DynamicData" Version="9.0.4" /-->
     <PackageReference Include="Material.Icons.Avalonia" Version="2.1.10" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="8.0.8" />