Hey everyone, As you can see from my signature, I run an Eheim 2213 along with my 85lbs of live rock, 4"DSB, a skimmer on steroids, and a 20g sump with a refugium. I suppose a lot of you are wondering WHY? Well, I keep a big bio-load. Right now I have around 20 corals and 10 fish in a 58 gallon tank. I've had many of these critters close to 2 years, so they aren't little either. I have to empty my skimmer's collection cup every day because about 1 cup to 1.5 cup of really nasty skimmate collects in there every day. Which is where my Eheim comes in. My Eheim is not packed like a normal canister filter. It has no pads, or sponges, or paper, or floss, or anything like that. That stuff just collect detritus and become a nitrate supplier, rather than a nitrate eliminator. I pack my Eheim with ceramic media on the bottom, sintered glass in the middle, and coarse (6mm) aragonite on the top, so that it acts more as a mechanically driven biological filter, than a mechanical filter. Here's a schematic to help you visualize what I'm talking about: It is true that the microscopic pores in the sintered glass and the coarse aragonite get full of detritus over a period of 2 to 3 months, and then the law of diminishing returns begins to take effect. So, what I do at that point is take the media out, and carefully wash it in tank water (during a water change), so that I lose as little bacteia as possible. Yes, I lose some, but over the course of a week or so, it is back up to full filtration again. I just thought I'd share this technique with you. Some of you may have problems with nitrates. This will help reduce your nitrates significantly, but you do have to keep the filter clean. It is not just plug and play --- you have to monitor you nitrate levels frequently, and when you see them beginning to rise, it is probably time to wash the filter media (and do a partial water change). I hope this has helped someone. Peace to all of you. ;D Edit: I just thought of something that I should have mentioned. The 2213 has a spray bar for tank return. This helps facilitate gas exchange tremendously. If you are considering getting a filter withouth a spray bar return, be sure and order one for it. You won't see as good results without the spray bar gas exchange.