Clean your patio easily with this 5L Xtreme Multi-Surface Cleaner by SmartSeal. This fast-acting patio cleaner has four powerful active ingredients that effectively remove black spots, algae, mould, dirt and staining often seen on patios. It also has a unique blend of cleaning surfactants formulated as a more effective alternative to Sodium Hypochlorite. With the fast-acting formula, it ensures a swift and efficient cleaning process. Only eight litres of this product will clean and treat approximately 40m² of patios, drives, roofs, decking, brickwork, natural stone or concrete surfaces, but always remember to wear appropriate safety gear all the time while applying it. Also, the surface must remain wet for 60 minutes, as the product becomes inactive once dry. Afterwards, you can wash away it with water from the hose or pressure washer and for areas of heavy soiling, scrub into the surface or re-apply. It will remove most ingrained organic matter and grime after one application, but sometimes, a second application may be required to remove all black and white spot algae.