“Tried Blackspot remover on faced concrete patio slabs with heavy blackspot/lichen growth. Used hand sprayer to apply. Tried one area 50/50 with water - kept dampened after application, washed off after 1 hour - result very good. Other area (heavier growth) used neat, again kept dampened after application, washed off after 2 hours - result good, but will need 2nd application to remove stubborn black spot areas. Am happy enough with the results. Will be intrested to see how long the black spot is 'held off' from the surface after tyreatment.”
