My wife and I set up a pond a few weeks ago after acquiring a used stock tank. The tank is 4 ft diameter and about 2 ft deep. I buried the tank almost half way in the ground to help prevent completely freezing in the winter. I decided to go with a bog filter so I went to the local farm supply store and bought a oval tank for the bog. It measures 2ft x 2 ft x 5 ft. I put a grid of pvc pipe in the bottom to disperse water flow. I put a layer of lava rock then filled the rest with pea gravel. I have water canna and horsetail and a pitcher plant in the bog so far. In the tank I have 2 Lillies and water hyacinth and 6 goldfish