re: Cleaning a pond, aeration, and other ideas.

If your goal is to kill algae copper sulfate is cheap and works well. The upside it will clear your pond.

The downside is if you plan on eating fish from the pond. If the concentration of copper builds up past 1.5 part per million it can become toxic. Also if you treat too much of the pond at once and kill too much algae at one time the dying algae will consume all the oxygen out of the pond and kill the fish. Gars and catfish will probably live but bass and perch will die. Gar and catfish can live in low O2 water better than bass and perch. So just treat a small part of the pond at a time if that's possible.