diff --git a/floatpump/Core/Src/main.cpp b/floatpump/Core/Src/main.cpp
index 34df88e..8db61a0 100644
--- a/floatpump/Core/Src/main.cpp
+++ b/floatpump/Core/Src/main.cpp
@@ -231,7 +231,8 @@ int main(void) {
         {
             dly_disp = HAL_GetTick();
             display.LCDSetBacklight(S_backlight);
-            char buf[20];
+            //Increase to 21 -> crucial bug! usually never use sprintf! TODO: find another option instead!!!!
+            char buf[21];
 
             display.LCDSetCursor(0, 0);
             sprintf(buf, "Fuellstand    %3d %%", tankLevel0.getPercent());