Purchased this filter with my 55 gal setup. The filter itself is fantastic works flawlessly with no leaks, even in a power failure (given the o-ring gasket is properly lubed), and has a decent flow. If its taken care of, it will not fail you. I believe that the large amount of surface area provided in Subtstrat Pro (Eheim filter media (German)), helps to keep the toxins in my water to a minimum. However, the manual will prove to be useless, and you will be left to your own devices to set it up. It also took a while to figure out how to prime the thing, but I could always help out with that for those who get stumped.