Over the past couple of years the pond has started to deposit a layer of "sludge ?" on the pond plant leaves, rocks etc ( If it was inside a house you would say years of dust, a thick layer over every surface). The lily leaves get covered and die off. The picture shows some of the pond weed after a shake to "wash" it off but it soon returns. Goldfish are fine, no problems with them.
So what might it be and what is to be done.
Thanks
Brian.
So what might it be and what is to be done.
Thanks
Brian.