Efflorescence- What Is It?
According to the “ICPI” (Interlocking Concrete Pavement Institute), efflorescence is a natural process, in which a random white haze may appear on the surface of the brick, which is caused by lime or a water soluble calcium oxide that rises to the surface after repeated saturations due to rain or sprinklers. Efflorescence does not affect the integrity of the bricks and will usually resolve itself with time and exposure to the elements.”)
The proper sealing of concrete brick pavers can either retard or stop completely the efflorescence process due to the moisture protection achieved by the sealing process. However, this warranty does not state or imply that efflorescence will stop as a result of the sealing process.
In addition, oil based sealers will actually prevent the efflorescence from rising to the surface of the brick paver and get trapped under the sealer. The only fix for this is to strip the pavers of all sealer using a solvent or stripper to remove the sealer completely. Water based sealers, such as Seal n Lock are a "breathe-able" product, meaning that the efflorescence can escape through the sealer and be simply washed away with a garden hose.