Well as above, Any of the Eheim folks have any comments? If it's ok let me alter the subject a bit. Are Most of you running the FX5 just as Fluval has recommended or do you have any changes you make? Again as most of you can tell I'm am not from a background in Marine Biology. I have been reading many articles that have been done that are very scientific allot which is over my head but what it boils down to is surface area and the amount of time required for the Bio filtration to occur. In short they claim that moving this water past the Bio filtration as fast as possible may not be the best answer. IE look at the study of the 2080 vs. FX5 where the Eheim cycled a tank almost two days quicker than the FX5 my point being that maybe this also holds true for not just Eheim but the Rena and others with a large volume? Is there anyone on the forum that has a background with Marine Biology or close that maybe explain this better than I. In short again maybe GPH isn't the beat all when it comes to filtration. I wish I could quote the exact articles but being from another forum source I'm not sure its allowed. This guy is smart wish he was on here to chime in, it make for great conversation. So, we have concluded that people love the FX5 it fills a nitch so to say. So if you are willing lets trying altering the subject from just I love my FX5 to actual explains of your FX5 systems, how many do you run, how are they configured, etc. And yes some of this may be comparision to other filters. I'm not trying to drag it out more but see if maybe more detail would keep from making it boring? 100 people saying I love my FX5, and nothing else I would agree thats old news.