Garbage collection with Using or Dispose

[trogalko]

Hi, I just get this error : The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached on an ASP.NET application that rely heavily on EntitySpaces.
Is that open/close db connection automatically disposed? so we should be bother to use Using "Bracket" to dispose? or there is any way to safely dispose unused connection, whether it is successfully executed or triggered an exception?
Thank You.