diff --git a/ErsatzTV.Application/Scheduling/Commands/ReplaceBlockItemsHandler.cs b/ErsatzTV.Application/Scheduling/Commands/ReplaceBlockItemsHandler.cs
index 7eb22e09d..140c973b7 100644
--- a/ErsatzTV.Application/Scheduling/Commands/ReplaceBlockItemsHandler.cs
+++ b/ErsatzTV.Application/Scheduling/Commands/ReplaceBlockItemsHandler.cs
@@ -68,8 +68,8 @@ public class ReplaceBlockItemsHandler(IDbContextFactory<TvContext> dbContextFact
     
     private static Validation<BaseError, Block> MinutesMustBeValid(ReplaceBlockItems request, Block block) =>
         Optional(block)
-            .Filter(_ => request.Minutes > 0 && request.Minutes % 15 == 0)
-            .ToValidation<BaseError>("Block Minutes must be a positive multiple of 15");
+            .Filter(_ => request.Minutes > 0 && request.Minutes % 15 == 0 && request.Minutes <= 24 * 60)
+            .ToValidation<BaseError>("Block duration must be between 15 minutes and 24 hours");
 
     private static Validation<BaseError, Block> CollectionTypesMustBeValid(ReplaceBlockItems request, Block block) =>
         request.Items.Map(item => CollectionTypeMustBeValid(item, block)).Sequence().Map(_ => block);
diff --git a/ErsatzTV.Core/Scheduling/BlockScheduling/BlockPlayoutBuilder.cs b/ErsatzTV.Core/Scheduling/BlockScheduling/BlockPlayoutBuilder.cs
index 560e76fcb..4fc038233 100644
--- a/ErsatzTV.Core/Scheduling/BlockScheduling/BlockPlayoutBuilder.cs
+++ b/ErsatzTV.Core/Scheduling/BlockScheduling/BlockPlayoutBuilder.cs
@@ -56,14 +56,29 @@ public class BlockPlayoutBuilder(
             BlockPlayoutChangeDetection.RemoveItemAndHistory(playout, playoutItem);
         }
 
+        DateTimeOffset currentTime = start;
+
         foreach (EffectiveBlock effectiveBlock in updatedEffectiveBlocks)
         {
-            logger.LogDebug(
-                "Will schedule block {Block} at {Start}",
-                effectiveBlock.Block.Name,
-                effectiveBlock.Start);
+            if (currentTime < effectiveBlock.Start)
+            {
+                currentTime = effectiveBlock.Start;
 
-            DateTimeOffset currentTime = effectiveBlock.Start;
+                logger.LogDebug(
+                    "Will schedule block {Block} at {Start}",
+                    effectiveBlock.Block.Name,
+                    effectiveBlock.Start);
+            }
+            else
+            {
+                logger.LogDebug(
+                    "Will schedule block {Block} with start {Start} at {ActualStart}",
+                    effectiveBlock.Block.Name,
+                    effectiveBlock.Start,
+                    currentTime);
+            }
+
+            DateTimeOffset blockFinish = effectiveBlock.Start.AddMinutes(effectiveBlock.Block.Minutes);
 
             foreach (BlockItem blockItem in effectiveBlock.Block.Items.OrderBy(i => i.Index))
             {
@@ -73,6 +88,17 @@ public class BlockPlayoutBuilder(
                     continue;
                 }
 
+                if (currentTime >= blockFinish)
+                {
+                    logger.LogDebug(
+                        "Current time {Time} for block {Block} is beyond block finish {Finish}; will stop with this block's items",
+                        currentTime,
+                        effectiveBlock.Block.Name,
+                        blockFinish);
+
+                    break;
+                }
+
                 // check for playout history for this collection
                 string historyKey = HistoryDetails.KeyForBlockItem(blockItem);
                 //logger.LogDebug("History key for block item {Item} is {Key}", blockItem.Id, historyKey);