1st time cleaning pool, why do I have this blue ring around my suction hole?

See the bottom hole:
http://i146.photobucket.com/albums/r...psnsrstrte.jpg

This ring is not removable no matter how hard I pull on it (with pump off of course). This ring is blocking me from connecting my pool vac tube to the suction hole.

I can really use the help. I need to clean the pool.