Algae on aoncrete/cement surfaces

[derrynoose]

Is there a substance which will clean algae from a concrete/ cement surface without endangering a tarmac drive adjacent to the area being cleaned?

[patricia53]

I've used something called Amillatox or something like that - smells like Jeyes Fluid but works.
Got it at a garden centre.

[nonomaybe]

Or maybe a good pressure washer will do the job without the need to use chemicals.

[janbee]

I use a pressure washer. Does the trick

[woodchopper]

armillatox is the best stuff for it.