Correct A Sparks! When a pond is relatively still there are a couple of things you can do to fix it, wait for the cool weather or as most here do put an impeller in the water to creat movement. It looks like a fountain in the pond but is very effective.Algae seems to form every year at some point on parts of the river and canal near where I live. I think the sunlight intensifies it.
It could also be Duckweed which can completely cover a pond in no time, it's now thought to be a new superfood for humans and not just Ducks. In the video you can see them harvesting itA quick view taken earlier today over the tops of the bushes shows the pond is green with algae.
This is an excellent newsletter giving wonderful insight into Tolkiens childhood and influence on this writing!The Mills archive has just posted this in their newsletter
This includes a link to the material they have on Sarehole. I do not think this link has been posted before:
Sarehole Mill, Hall Green - Archive Catalogue
Welcome to the Archive Catalogue of images and documents relating to our milling heritage.catalogue.millsarchive.org