I am setting up my filter for my reef. I have a 55, and I would like to have several fish, so my bio load is going to be fairly high. Thus, nitrates will be a problem, so I am thinking of using a coil denitrator. I think that a 50 foot coild of hose is acceptable, but I'm not sure what to use for the media. I was going to get the simple bio-balls, but then, I was reading about the fluidized sand filter, which isn't supposed to clog and is supposed to have more surface area. Can I use sand in the denitrator? What do you guys use? Does anybody actually use a denitrator?