I bought this unit as it was exactly what I needed for my pond. It worked great the first year. Luckily I was able to have Farm Innovators replace it under warranty as it was just within the 1 year period. Again, same thing, the replacement unit worked great the first year but some how got water in it(like the first one), now it melted through the bottom of the unit and is useless. I did not submerge the unit as it floats on top of the water but it appears that the seal around the plug cord going into the unit is poor and lets water seep in....luckily I have a small pump circulating the water that keeps a small opening in the ice so the fish are still swimming. I have to look for different unit for the real cold weather, what a disappointment.