controlling moss and algae

Jeyes Fluid will damage tarmac and Armillatox is not strong enough now.
I've used Sulphate of iron but it does stain paths, tennis courts, driveways etc. a rusty colour.
You can jet wash it off.

I dont normaly take to this kind of thing but living withvery shaded back yard to my house and having spent a fortune over the years I felt a great sympathy with your problem----the answer to my own ( that I discovered by dint of trial and error ) I am forwarding and hope that it will be the little miracle for you that it has been for me/ Go to somewhere such as Lidls and buy some of their liquid detergent(I bought the 1 litre concentrated ) on my steps and paving stones I painted it on neat then just left-- no scrubbing -hosing-and it worked--try and choose a dry spell I didnt have any problems of slipperiness with it either--it also worked equally well with equal part cold water to dilute it on the mossy tarmac at the font of the house Do try it please if only on a small area initially--have a little patience it may take a little while to see the efects but the effcts are quite long lasting and so easy to paint on I dipped a soft sweeping brush into a large bucket and scrubbed it into the porous surfaces then left --that was lastJuly and my steps and breeze blocks are still clear --I have never gone a winter before without dreading Spring and all the scraping and prodding and scrubbing I would have to do---Good Luck if you try this and hope you have the same success-- Highsteps

If you don't want to use chemicals (they cause havoc if they run off onto flower beds) use a power washer to blast it all away. regular sweeping will help too.

you could try a strong solution of bleach in a watering can fitted with a fine rose and then use a stiff yard brush