I'm on a 'blogging roll' at the moment. Mentioned to OH about the Algae on the block paving at the back of the house, he said if algae is growing (not moss, fungi or mould) then it is a place free of pollution, this is why it's good to see Algae on a roof. This is were I sit to get my Vit D, in the warm sunshine which I am expecting any day now.
Lib x