"Paul" wrote:

Was wondering if someone could tell me why i have algae growing only
where the water returns into the pond.It seems to grow from the rocks from
which the water runs over. Everywhere else there is no algae in the pond.

String Algae is filtering out nutrients as they enter the pond to stay
alive. Moving water brings nutrients to the algae, so water that is low
in nutrients will bring the nutrients to the algae where there is flow.
Apparently it is doing a good enough job to make the rest of the pond
not receptive to more string algae growth. Also, there is no flow in
the rest of the pond so that string algae doesn't grow.