I have used this product for one season. It really did what it said it would which was clean my rubber roof without damaging it. The clean I got from this product was exceptional. With a little bit of scrubbing my roof was once again nice and white. Also the UV protection that this product offers appears to do what it says it would, protect the roof from damaging UV rays. The 4 liter jug will wash your roof three times. Use one third of the product mixed with the same amount of water to create your cleaning solution. Then put it all into a chemical sprayer and sparingly spray your roof and scrub. The solution should last a full 32ft of roof.