I have always been a Eheim guy. I had a lot of success with the pro2 that they don't make anymore. Right now I am running two 1200 pro 3 's and I have mix emotions on them. The pre filter pad is on the top and then water runs to bottom of the canister through a corner tube in the filter. I am using the Eheim pro round media balls and some bio-home plus media. Every week the filters have tremendous debree free floating in the water in the canisters (brown water). The water in the tank is clear but has a brown tint to it. I do water changes every week. The tank is a 180 gal and was set up about 4 to 5 months ago. I do have a piece of drift wood in the tank but when I removed it the tank was still getting brown after the water changes. I don't know whats going on. The fish are fine , I am feeding once a day, and the tank is not over populated. My friend has the Fluvials FX6 with a lot more fish in his tank and he hasn't opened them in months. Any one have suggestions on whats going on in my tank ??? Any one using these EHEIM 1200 XL filters with issues ?? Again I was always a Eheim Guy but these new filters with the double intake lines I am not so sure about.