When I sailed on the Millennium the Thalassotherapy pool was free. When I went on the Century the Thalassotherapy was inside the spa area and their was a charge. However; if you were in the Elite repeaters level it was complimentary.
From what I have read on the Celebrity website that particular pool is included only on the Mellenium class ships and is an extra fee on all other ships.
Dr. Bob...we just got off Galaxy to Panama. There is an enclosed pool behind buffet area that is open to public. I do understand there is a pool in the aquaspa that is for a fee. We didn't venture there...not about to pay to swim. We did get in the outdoor pool though. Galaxy OK ship. You will be impressed with the Canal...some other stops were not our favorite.
Actually, the solarium pool on the Millennium calss ships is free for adults over 18 (no children allowed) and is the result of the combination of the solarium swimming pool and the Thalassotherapy pool in the Aqua Spa in the earlier class of ships. I believe there is a $10 per day fee to use the Thalassotherapy pool on the earlier class of ships. Elite members on Celebrity (10 or more cruises on Celebrity or Diamond status on RCI) enjoy free access to the Thalassotherapy pool.