When I was on the Zuiderdam last may I took a tour of the greenouse spa. I didn't want to pay $150 for use of the hydrotherapy pool and thermal suite for 7 days but the woman could see I was interested in the facilities. A day later I received an invitation in my room for use of both at half the cost for the rest of the cruise, which I took them up on. I'm hoping to get something similar for my 17 day cruise to Hawaii in September. I was in a full suite on Zuiderdam so I don't know if the special price was due to my cabin size or not.