Okay, so I have kept and bred african cichlids now for almost 3 years. I have a very successfull breeding colony in a 55 gal, and a 40 gal grow out tank. I really like discus, and previously kept a few in the 40 gal, but now I have an idea. I have a 20 gal tank that is actually a mantis shrimp/reef tank. If you have never heard of a mantis shrimp, do some research!! I know how to plumb tanks up, and I would like to make a Calfo style overflow in my 55, have it drain into the 40, and use the 40 as a sump/refugium type system. I would of course have a 800 gal per hour pump on the end returning the water back up. My main question is, what kind of filter media should I get for in there? I don't really like Bio-Balls at all, and want to stay away from them if possible. I would of course run a little carbon in the system, and I would like to have a planted tank. I would like to have some plants in the 40 gal which would help in the filtration. Are there any that I should get? Would having those plants down there be redundant? I like the fact that I would have about 75-80 gallons of water going through the 55. Having this extra water would allow me to have a better way of keeping the water parameters in check without having huge swings in it. Guys, I know A LOT about fish, both fresh and salt, and I know enough about Discus to be dangerous, but I want to get the best info that I can from the experts out there!!