Hi everyone! I have a 15 ft by 15 ft side yard that will be fenced off for my two ducks. They will live back there all the time, but I may let them have reign of the yard once in a while. Anyway, I wanted to transform the side yard into a natural looking habitat with plants and also a in - ground pond. The pond will have no fish or plants in it, so I was wondering how much filtration will be needed for it. Also, what do you think he minimum size should be for a pond in that area? I want to make it as big as possible, but still give the ducks plenty of room to roam on land. Thankyou all!