Dear Claire:
The installation has nothing to do with it. The problem you're reporting is very common with low-grading travertine from Turkey. You can fill the holes either with unsanded grout. Keep on the thick side and push it deep inside the holes. Or you can opt latex-based siliconized color-matching caulking material. That one too has to be pushed as deep into the holes as possible.
May I ask you now to please read and e-sign our Statement of Purpose at:
http://www.marblecleaning.org/purpose.htm?
Ciao and good luck,
Mauri
Article ID: 1564
Created On: Fri, Jul 18, 2008 at 1:17 PM
Last Updated On: Fri, Jul 18, 2008 at 12:00 AM
Authored by: Maurizio Bertoli [mail@mbstone.com]
Online URL: https://marblecleaning.org/knowledgebase/article.php?id=1564