The Biocel Chlor-Kleen Double Strength 20L is a highly effective cleaner designed for paths, patios, and other concrete surfaces. This double-strength formula removes green algae and staining at half the usage rate of standard sodium hypochlorite, making it a more efficient choice for large-scale cleaning. It works to return surfaces to a like-new condition with minimal effort. This 20L container is ideal for professional cleaners or homeowners with extensive hard surfaces to maintain.