Connections in Pool Not Being Reused

I have a form that has a number of database calls. It does these sequentially. In some cases it's not possible (due to archetecture more than anything) to make these calls all on the same connection. However it does open then close the connection. (all connections created are in using statements)

What I'm seeing is that we're getting a timeout when the 100 connection limit is hit. Looking at Activity Monitor I can see these connections growing and growing over time in the activity monitor the more windows you open and close even though these connections are closed. (and they all use exactly the same connection string)

I read that it might be because of SQL Debugging being turned on in vs.net, but that is not enabled in either debug or runtime for us and we're seeing it in client sites as well as locally.

We're running .NET 2.0.

Does anyone have any ideas as to why it won't reuse these clearly properly closed connections?

Thanks!

Does it happen even with a connection alias ? For more information, please refer http://blogs.msdn.com/sql_protocols/archive/2007/01/07/connection-alias.aspx|||Are the connections using the exact same connection string so you can take advantage of connection pooling? Even with a using block, you might want to try to explicitly close the connection.|||

Yes, they're using the exact same connection string, and yes I tried explicitly closing the connection and while it shows as waiting instead of inuse in the Activity monitor after doing that, they will not be recycled. If I dispose of the form that the connection is on (which is a custom drop down for a custom combo control) then it gets released and the connection gets reused.

I'm not using conneciton aliases. I have yet to see the point.