Has anyone ever seen any other type of heater for an aquarium besides the traditional tube shape? I am specifically looking for one that will fit in my sump. Problem is the water where I could put it is only about 8" deep. A tube needs to be around twice that long to provide heating for my size tank. The alternative is buying multiple small wattage heaters that are short enough to fit in there. I am also looking at inline heaters which may be the best option.