I have a 60 gallon saltwater tank on laminate flooring in my living room. It hasn't been an issue.
I didn't place anything under my stand as it doesn't have the separate legs that would be applying pressure to the flooring, its one piece that sits on the floor.
I do keep towel handy when I'm working on the tank and lay one large one down in front of the tank to prevent any water from hitting the floor. I can't imagine the saltwater being good for the floor.