Answer:

Test to be sure the swimming pool is properly balanced. If so, it is likely safe to swim. As for the ducks in the pool, there are some things that you can do to keep them out - place a solar cover on the surface when not in use, try a large windsock somewhere around the pool or use inflatable or rubber decoys (snakes, owls, etc.) that would keep the ducks out. These may work well, but ducks sometimes realize they are fakes and come back. Also make sure your pool is clear - no leaves, sticks or other debris that makes the pool look more welcoming to ducks.