Im gettin a 300 gal for my 22in red belly pacu. The tank is reef ready (as it has the hole in the glass for a sump). When the fish dieds hope not for a long time, but if it does it will be saltwater. So im lookin for a freshwater filteration set up? The fish has very big waste and thinking of needin alot of mechanical filteration. I heard that a sump in a fresh water is not what you want. I have been looking at the fluval FX5 with a aquaripure nitrate filter. Soo what do you guys think???????