Filtering salt water

Question
I built a salt water pond in my yard.  I have a pump that pumps salt water into the pond.  I also have a pump that constantly recirculates the water and filters the water through a standard pool pump filter.  The water is very clear but the pond is lined with rocks on the sides and some sort of algae is growing on the rock. what is causing the algae to grow on the rocks and how do I get rid of it.

Answer
firstly may i ask why you built a saltwater pond? just intrigued as to what your gonna put in there.

the algae is a normal process that the pond must go through, called cycling. to be honest you will always get algae as its in direct sunlight, there is no way to stop it growing apart from take away its food supply i.e. light, nitrates, phosphates etc