Pond water suddenly goes brown.

NewBoy2

Over a period of about 5 days the water in my allotment pond has gone slightly brown with some brown foam on several parts of the surface.

I have several plants and some added pond weed and there is life as I have froglets , pond skaters and some newts.

??

Dovefromabove

It's probably a brown algae .... it usually disappears of its own volition, but Blagdon's pond treatments are fine for wildlife ponds and will sort it out.  

https://www.blagdonwatergardening.co.uk/Products/Test-Kits-Treatments/Green-Water,-Dirt-Algae