Hi, I am getting a 125g tank next week and it is already drilled from a previous marine setup. I have never had a tank this large was curious about suggested filtration. The pipes are damaged and would need to be redone. The price of getting a Fluval FX6 or Ehiem pro 3 is not an issue and if that would be enough filtration, may be preferable to a sump as I have no experience piping or plumbing. If the sump would be better, I could try and learn that though. My stand is 74" by 20" by 30" tall. My planned stock for the tank is 3 rope, 1 eel or bichir, 3 butterfly fish, 1 leopard ctenopoma, congo tetras, african knife, and a synodontis catfish. I know the eels can climb into the FX when it shuts of but I was planning on sealing any pipe with screen or larger mesh in which the eel couldn't escape. Suggestions?