So Im getting ducks this spring. 5 to be exact. This is one aspect im not sure about, as ive had conflictin results from the internet. so our pond is (im going to try to describe it as well as possible) not moving water, its water level, though nearly flush with the ground, the water table is right below ground level. its circular, about 20 feet around, with a small island in the middle. it is 3-4 feet deep in all places, there is not really any slope from ground level to the bottom, its a straight drop, though past ducks have had no problem gettin in and out. so my dilema is, does it need to be filtered? And if so what kind of filtration system do i need? any help is appreciated.