These tiles were put down 5 years ago and only about 6 months ago began
showing this.  I believe it is the sediment (salts, etc..) finally coming
through after the years of getting wet and drying out.  Is this correct? All
they have tried is acidic cleaners (strong ones) Either way, what is it and
how can it be fixed?

Lorne Greenberg
Fabra Cleen
"Getting all the dirt since 1949."
212-777-4040, 718-776-3564
516-377-0993
www.fabracleen.com
www.fabracleenstoneandtilecare.com