There is only two reasons why the product hasn’t been 100% successful, either not enough product has been applied to the contaminated area or is has been rinsed off too soon.
NEVER rinse the cleaner off until all the Black Spots have turned completely WHITE. If most of the Black Spots have started to turn white but a few are still Black, apply a little more product.
Always Do a Test Area before proceeding with the rest of the patio.
Any problems please call our technical helpline where we will be happy to help and advise. 01300-345898