Most white limestone patio owners scrub blisters into their hands every year using bleach to remove molds and algae, and if they own a power washer, cause annual stone and grout damage due to excessive high pressure power washing.
What actually happened here and is happening at every unprotected home is damage caused by water penetration. Water can easily penetrate any stone, brick, or masonry material and grow mold inside and below the surface of the rock. It makes the stone ugly and serves as a breeding ground for molds behind or underneath the stone. NANO1000 completely saturates and impregnates the stone below the surface, stopping water penetration. If any mold or algae is seen after the application it is growing out of surface dirt and can be easily removed with a garden hose.
Most white limestone patio owners scrub blisters into their hands every year using bleach to remove molds and algae, and if they own a power washer, cause annual stone and grout damage due to excessive high pressure power washing.