How do you open the sealed chamber?
Make sure you have a Relicanth(teach it Dig), and a Wailord.
When you first enter the secret cave on Route between Pacifidlog
Town and Slateport City, you will go in the middle of the brail
symbols located on the backwall. Read the inscription, then use
dig. The wall will open. Go inside and go to the middle of the
brail symbols in the back of that room. Make sure that you have
Relicanth in the FIRST slot of your Pokemon party and Wailord LAST
slot of your party. Read the inscription on the wall and then three
doors will be heard unlocking. They are located on Routes 105, 111,