Duck pond... will always be dirty to some extent. The chore is to keep it clean and filled with fresh water on a regular bases. We purchased a 320 gallon stock tank a few years ago. Built a ramp to it and they love it, but I have to clean it often. During summer months I may get only 3 days between complete drain and cleaning. As some one has posted... the "poop soup" makes great fertilizer. I drain the pond near back yard trees. Wonderful tree food as well as garden. We have well water so no problem with water expense.