By Borodin
Denbighshire,
United Kingdom 
This isn't a question but a recommendation. For anyone with patio stones / driveways / garden ornaments that are covered in moss or algae then have a look at a product called Wet and Forget which is available on the QVC website. You buy 5 litres which will give 30 litres of mix which will cover between 100m2 to 300m2 depending on porosity of the stone / material. It stays soaked in and then is activated when it rains. I honestly saw results after just three days and I assure you that I need impressing before I endorse any product. It isn't inexpensive (About £40 inc delivery for 5Lts) but then it certainly isn't a 'cheap' product. I bought an 8lt hand pressure sprayer from EBay for £8 and the results after applying this stuff are simply amazing. Try it....
18 Apr, 2016
Answers
It can last 12 months, even longer but basically if you see re-contamination give it another spraying. Its quite amazing to watch it activate when it rains.Like I said, it's relatively expensive in comparison to other products but it does the job with very little effort required from yourself.
20 Apr, 2016
Previous question
there is a product for everything these days. then there are people asking for products to encourage growth of algae moss on ornaments to give them an aged look. haha.
£40 sounds a lot to me. how long does it stay effective for?
19 Apr, 2016