We just had our Bain Ultra Thalassa tub installed, which is used as a shower combo. I love the tub, but thought that it had a skid-proof or textured bottom. Apparently I was wrong.

What does anyone recommend to put on the floor of the tub so you don't slip? I don't want to put down those adhesive strips that will cause stains or ruin the bottom of the tub. What about those mats, the nicer ones that are sold at Bed Bath & Beyond? It's an expensive tub and don't want to ruin the finish, not to mention the looks of it.