The Natural Philosopher wrote:
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?

Green goes with bleach and heavy power washing. Its the black ones that
are impossible to shift.

Does everyone *really* worry all that much about what colour their
patio paving ends up as it weathers? Our patio paving (two areas
outside sliding doors outside the house and one area round the pond)
just get cleared of the weeds that pop up through the cracks and
that's it. If they go funny colours with lichen or other such things
then that's part of their attraction IMHO.

You don't clean all the funny patches off the bark of beech or silver
birch trees (or do you).

--
Chris Green
·