Best option for painted render?

[Moor]

I’ve been asked by one of regulars to clean the algae film on his painted render on the house and paths. He’s looking for the longest acting treatment possible, and I wanted the easiest solution to this, he’s also no bothered if it’s an instant solution as long as it works and won’t come back too soon.
I’m reluctant to use hypo due to the leaded windows, I was thinking a Benz softwash?
If I go with that route, what’s the time between applying and allowing water onto the affected areas (I need to clean the windows too)?

 

[Pjj]

I’ve been asked by one of regulars to clean the algae film on his painted render on the house and paths. He’s looking for the longest acting treatment possible, and I wanted the easiest solution to this, he’s also no bothered if it’s an instant solution as long as it works and won’t come back too soon.
I’m reluctant to use hypo due to the leaded windows, I was thinking a Benz softwash?
If I go with that route, what’s the time between applying and allowing water onto the affected areas (I need to clean the windows too)?

Go on Benz website they have a very comprehensive q&a section it will answer all your questions, it will come back though , but so many factors are involved it should stay looking good for 12-18 months at least BUT if it’s a very damp shady area can come back with a few months , the product you want is the Benz bio clenze not the lightning clenze as that’s hypo based . Depending how bad it is put 1 ltr into a 25 ltr drum and fill with tap water apply to wall with spray or through your window cleaning brush it will kill green algae within 30 muinits ,red ,black algae can take a few days weeks ore months to die so don’t expect instant results . Benz state if it rains within 12 hours a further application might be needed