You just have filamentous algae. Probably Spirogyra. Its tough to treat a pond with its temp below 60 degrees. Copper sulfate works and so does Cutrine Plus. Mix 1 pint of Cutrine and 2 ounces of surfactant per gallon of water. Shake it up good and spray it on the algae mats. I would avoid the boat drag method. It works good but its old school and can add way too much copper to your pond.