Session / Login help

[eluser]gbd_dee[/eluser]
Im new to CI. I want to restrict views to logged in members of my site. Im currently using session class but not sure if its working correctly. When I destroy the session I still have access to restricted content. Can someone go into detail on how I would code this correctly.
Every user has a profile page (only the logged in user can access its own person profile information/page)
Profile controller

Basically I want to only allow a session to be active for 30 minutes without activity, if a window or tab is closed I want the user to have to login again.

I need a code snippet that I add to every view that I want protect from non logged in members. Thanks in advance