Hi, I bought a filter on eBay for £1 not knowing what model or size it was so when it was delivered I searched all the writing I could find on it through google and came to the conclusion that its Chinese and the company that builds them is a suplier of sun-sun. (heard of them before but no idea on quality) Anyway, it has two filters stacked on top of each other then the powerhead on top of that which has more kick than a horse and turned my 3' tank into nigra falls and scared my fish half to death. I've now fitted a hose down the length of my tank and turned it into a giant spray bar and it doesn't seem to annoy the fish anymore. ??? Is it a good idea to have such a massive filter in a tank so small??? Can you overfilter?