Have you taken any moisture reading on this floor? it could be efflorescent . have you tied to test removing with an acid based cleaner? If so what were the results?
From: Roger Konarski [mailto:qm144@yahoo.com] Sent: Sunday, February 23, 2014 10:02 PM To: Stone and Tile PROS Technical Support Subject: [sccpartners] Bad
Case
Please see the attached picture. Is this a bad case of efflorescence ?