I am reasonably certain Carnival has salt water in all their pools, including the Liberty. Princess, as noted by Penny, has freshwater in all of their pools. Royal Caribbean has switched to freshwater in the Freedom class ships, but I think they still have saltwater in their other vessels.
Originally posted by penny3333:
The only ships I know of that use fresh water are Princess ships.
I bet that is nice I love the water but the salt water burns your eyes like crazy, I know I can use goggles but I guess I just wont put my head under the water.