diff --git a/definitions.go b/definitions.go
index cf14d179..5102def8 100644
--- a/definitions.go
+++ b/definitions.go
@@ -110,6 +110,7 @@ const (
 	xPubIDField          = "xpub_id"
 	xPubMetadataField    = "xpub_metadata"
 	blockHeightField     = "block_height"
+	blockHashField       = "block_hash"
 
 	// Universal statuses
 	statusCanceled   = "canceled"
diff --git a/model_transactions.go b/model_transactions.go
index 1bbfe69d..8094ea08 100644
--- a/model_transactions.go
+++ b/model_transactions.go
@@ -950,7 +950,11 @@ func processTransactions(ctx context.Context, maxTransactions int, opts ...Model
 	}
 
 	conditions := map[string]interface{}{
-		blockHeightField: 0,
+		"$or": []map[string]interface{}{{
+			blockHeightField: 0,
+		}, {
+			blockHeightField: nil,
+		}},
 	}
 
 	records := make([]Transaction, 0)
diff --git a/tasks.go b/tasks.go
index 56e8fd27..dd771f4a 100644
--- a/tasks.go
+++ b/tasks.go
@@ -108,5 +108,5 @@ func taskCheckTransactions(ctx context.Context, logClient zLogger.GormLoggerInte
 
 	logClient.Info(ctx, "running check transaction(s) task...")
 
-	return processTransactions(ctx, 10, opts...)
+	return processTransactions(ctx, 1000, opts...)
 }