For the first winter we had our pond, I read all the advice about winterizing and bought a heat ring. It worked fine and kept a hole in the ice for aeration. Second year, the ring malfunctioned and the pond froze over. I was sure that I had lost all my fish and plants, but when spring came, everything was fine. Fish were swimming and plants came back to life. Since then, I haven't done anything for the pond except sweeping as many leaves out as I could. I leave both the pond filter and the waterfall pump in the pond and they both emerge in working order in the spring as well. My pond is around 400 gallons and goes 18-20 inches deep as we enter winter number 7 . Am I just lucky or does anyone else use this slacker method with their pond in the winter?