On 06/11/2020 20:59, F wrote:
We've got a patio made up of light coloured concrete paving slabs with a
slightly rough texture. I've used a Karcher power washer to remove the
compost that the resident gardener has managed to tread into them but
there's a green stain (algae?) that's pretty resistant to removal.

Anyone got any suggestions on what might shift it?

Thanks, all. It looks like an order for BAC50 will be going in.

--
Frank