The white/Efflorescence showed up as the floor dried after we cleaned it. This is the second time we've cleaned the floor and according to my son, even less pressure was used. According to the home owner there was some "wicking" the last time but no where as extreme. The shower that is on the other side of the wall has really bad efflorescence on the 8" versions of the same tile. The staining on the far right next to the wall is from a cat litter box.. We sealed it with Cobbs after cleaning. My advice to here was to 1st, have a water damage guy come out with a infrared camera and try and find the leak form the shower. Fix the leak if possible than wash the floor with ammonia, let dry and wash again with vinegar.. Then use a Enhancer Sealer to attempt to hide the efflorescence.. And be prepared to do this every year or so or until you jack hammer out that overly porous tile.. What say YOU?