The extended period of water movement through the concrete to the surface brought chemicals to the surface where they combined with carbon dioxide from the air to produce calcium carbonate the white chemical you see in this photo.
Efflorescence polished sealed indoor concrete floor.
Efflorescence will not only cause problems with a stained and sealed concrete floor it can also delaminate tile and warp wood floors.
When moisture and water vapor migrate to the surface of hardened concrete floors walls and colored concrete it carries with it calcium hydroxide.
The stains are normally white and are present in darker colors more than white or pale colors due to the contrast created by the chemical reaction.
Efflorescence will not only cause problems with a stained concrete floor it can also delaminate tile and warp wood floors.
Efflorescence will be triggered by low temperatures humidity condensation and rain.
Concrete efflorescence is a very common problem on concrete especially decorative concrete.
The best approach would be to strip all the sealer and wax off the concrete.
Joe nasvik an example of extreme efflorescence.
Armor ar350 acrylic concrete sealer is an excellent choice to seal garage and warehouse floors and also works very well for driveways pool decks patios etc.
Once the sealer and wax are removed a moisture test should be conducted so you can get an idea of how much water is moving through the slab.
Concrete can be stained when salts and other materials will come off the concrete surface.