Well that depends... Do you want a swimming pool or a fishing hole?
Seriously, IIWM I'd wait and see if it gets to be a problem. What a lot of folks don't realize that treat with copper products is, copper is a heavy metal and it's over use can sterilize your pond as it doesn't completely break down in your pond bottom. Some filamentous algae is actually the sign of a healthy and diverse pond. On the other hand i guess there is
Green Clean if it really bothers you but it's not cheap.
One of my ponds has in the past had an over-infestation of Chara, Sago Pondweed, and Small Pondweed. It's due to all the nutrients from the feeding I do -- due to the number of large feed trained fish I raise -- for a couple of niche markets. To combat that I use
Aquashade at twice the recommended rate. Problem is, the nutrients have to go somewhere, and since they are not being utilized by the phytoplankton (no algae bloom) or the macrophytes, which are being held in check, they are being utilized by filamentous algae around the shoreline.
At first I was not happy with the appearance of the algae, but then i realized it acts as a natural break to the water pushed up against the shoreline as the pond level goes down. It keeps the bank from eroding from wind action .I know this because I raked all the algae out one day, and soon I had turbid water where the waves were lapping up against the receding shoreline. When the algae came back that stopped.
Best of all, this natural rip rap that was free, goes down with the water level as the pond goes down unlike rip rap. The frogs and tadpoles love it too.
Algae also breaks down ammonia which is a byproduct of fish feed and fish wastes.
