diff --git a/FrontendWebApi/ApiControllers/HydroMeterController.cs b/FrontendWebApi/ApiControllers/HydroMeterController.cs
index f87c8f9..b9d840d 100644
--- a/FrontendWebApi/ApiControllers/HydroMeterController.cs
+++ b/FrontendWebApi/ApiControllers/HydroMeterController.cs
@@ -67,11 +67,7 @@ namespace FrontendWebApi.ApiControllers
                                 ? input.startTime + "-01"
                                 : input.tableType == "month" || input.tableType == "year" ? input.startTime + "-01-01"
                                 : null;
-                var endTime = input.tableType == "day" || input.tableType == "week" 
-                                ? input.startTime.Split("-")[0] + "-" + (Int32.Parse(input.startTime.Split("-")[1]) + 1).ToString().PadLeft(2, '0') + "-01"
-                                : input.tableType == "month" ? (Int32.Parse(input.startTime.Split("-")[0]) + 1) + "-01-01"
-                                : input.tableType == "year" ? (Int32.Parse(input.endTime) + 1).ToString() + "-01-01"
-                                : null;
+                var endTime = DateTime.Parse(startTime).AddMonths(1).ToString("yyyy-MM-dd");
                 string sqlWhere = "";
                 string sqlGroup = "";
                 string sqlAvgRawData = "";
@@ -239,11 +235,7 @@ namespace FrontendWebApi.ApiControllers
                                 ? input.startTime + "-01"
                                 : input.tableType == "month" || input.tableType == "year" ? input.startTime + "-01-01"
                                 : null;
-                var endTime = input.tableType == "day" || input.tableType == "week"
-                                ? input.startTime.Split("-")[0] + "-" + (Int32.Parse(input.startTime.Split("-")[1]) + 1).ToString().PadLeft(2, '0') + "-01"
-                                : input.tableType == "month" ? (Int32.Parse(input.startTime.Split("-")[0]) + 1) + "-01-01"
-                                : input.tableType == "year" ? (Int32.Parse(input.endTime) + 1).ToString() + "-01-01"
-                                : null;
+                var endTime = DateTime.Parse(startTime).AddMonths(1).ToString("yyyy-MM-dd");
                 string sqlWhere = "";
                 string sqlGroup = "";
                 string sqlAvgRawData = "";