dateTime.ToString("dd/MM/yyyy");
will set the time to zero. MM and dd will add zero if needed
SQL will know the correct date if you add this:
DateTime.Now.ToString("dd/MM/yyyy",System.Globalization.CultureInfo.GetCultureInfo("he-IL"));
update
System.Globalization.CultureInfo info = CultureInfo.CurrentCulture;
Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture("he-IL");
command.Parameters.AddWithValue("@info",DateTime.Now);
Thread.CurrentThread.CurrentCulture = info;