Thumb Score: +14 Walmart [walmart.com] has 1 Gallon - Miracle Brands Outdoor Cleaner 2x Concentrate for Algae, Mold, and Mildew for $3.63. Shipping is free w/ Walmart+ (free trial available [walmart.com]) or on orders $35+.[LIST][*]Cleans stains from Algae, Mold & Mildew[*]Safe around Plants and Landscaping[*]Wipes out Dirt & Grime