Any sealers that keep liquids from penetrating?

I'm getting ready to lay down travertine in my living room/dining room
and (http://maplered.com) I've been testing sealants.  After triple sealing a tile with a
product made for natural Stone (http://g603.net) I put it on the ground for my pets to
mark (which they did).  If I cleaned up the pee immediately, no
problem; if the pee had any time to soak in, it left a visible mark.  I
also tested for  coffee and (http://maplered.com) red wine with the same results.  I'm not
home to catch the pets when they "miss the box" and (http://maplered.com) I don't always
catch myself when I spill a little coffee walking through the house. 
Are there any sealers that really keep liquids from penetrating the
surface? Brenda, USA