FluvalFX6 High Performance Aquarium Filter, Canister Filter for Aquariums up to 400 Gal.

The Fluval FX line of filters is a real work horse which rarely goes wrong if you do the upkeep on it. I use one on the tank I have my turtle in, and it keeps the water crystal clear, even though the old boy digs a lot an tries everything he can to cloud up the water. If I take it off line for cleaning (which is a breeze) or maintenance, it will get the water clear again within an hour if the turtle has been very active while it was off, and much sooner if he wasn't moving around too much. He's a very active turtle, and a very messy eater, but he's neither active enough nor messy enough to overwhelm the FX-6.I also use an FX-6 on my hillstream tank which requires a lot of flow. It pushes the water through at a very good clip so that the stream has a pretty good current for my hillstream loaches and for my rainbow shiners to run in when they're getting ready to spawn. I have the FX-4 on a 20 gallon tank which is probably just a bit overpopulated, But again, it is a good enough filter that it keeps the water quite clean. With surface skimmers on my tanks, even the water's surface is clear.To clean the filter media, all you need to do is lift the media baskets out, the use the filter's bucket to clean the sponges and reusable media, replace the media which has broken down too much to be reused, or which uses chemical treating, then either empty the old water out and replace it with fresh clean, or keep the old water if it's not too bad (it is almost always too bad). The reason you clean the media in the water the filter bucket has in it is so that you don't loose any of the beneficial bacteria which is growing in it.The FX series of filters have variable flow valves, which is a nice feature, though many filters have that. If you close the valves before opening the lid of the filter, you don't have to worry about draining the hoses, and they will be good to go when you turn the filter back on and open the valves. No priming needed. Everything in this filter is easily repairable if something goes wrong. If something happens which wears out the impeller, it's very easy to take the old impeller out, and drop a new one in. It's also easy to replace all the O-rings when they get old and start to loose their ability to seal the unit. If you're unlucky, you might need to do that once a year, but it's more likely that you'll just need put new lubricant on them. I am mechanically challenged, so if I find it easy to take care of, I'm sure just about anyone will be able to do it.I have had problems with several of the other big brands of filter makers, but I have never had a Fluval FX series filter go south on me. I recommend them to anyone who wants to keep their fish's environment clean and healthy. If I ever start another tank, I'll definitely be buying another Fluval FX.

Quite happy with the filter. My old cannister filter finally died, and I was trepidatious about changing brands. However, this was way easier to install, set up, and get running. Everything was included (except the activated carbon). Amazingly quiet. I just didn't notice how loud the old one was anymore I guess. Within an hour of running, it had reduced the turbidity in the tank noticeably. I'd recommend it.

FX 2 I have for a 55 gal, FX 6 for my 180 gal. These are the very best filter systems I have ever owned, and you can’t hear it run, it is perfect. THANK YOU

I bought an FX5 in 2011. Seven years later it is still running like brand-new.I bought an FX6 in 2013. Five years later . . . .like brand new.I've been keeping fish for more than 25 years. During that time I've used many different types of canister and HOB filters. My main recollection with previous canisters was the rage and frustration of priming them, fitting finicky rubber gaskets, dozens of fussy parts. . . After those experiences, the FX5/6 were such a joy. They're simple to assemble, and they prime immediately.Nothing is perfect, so here are pros and cons to help the prospective buyer:PROS:1. Huge capacity. Imagine a 4-gallon bucket filled with media, with a powerful motor in the lid.2. Moves a lot of water, and keeps the tank sparkling.3. Starts instantly and runs like a dream.4. Reliable - I've been running an FX5 continuously for 7 years; and an FX6 for 5 years. I've never once had any repair issues or problems of any kind. The only maintenance I do is clean or change the media as needed.CONS (and these would probably be better described as "things to consider before getting one").1. Powerful enough to suck up fish. In my 120g, I previously had jewel cichlids. They spawned, and whenever I would clean the filter I would find babies inside. Again, this is not a defect, this is just a cautionary note to be smarter than I was about where you use the filter. I currently have guppies in the 120g. They have hundreds of babies. Again, on any given day I'll find a dozen babies in the filter. (FWIW, you can adjust the flow, although I'd suggest that if you need reduced throughput, you might just get a smaller and cheaper filter).2. It's heavy and awkward. Hey, it's a 4-gallon-ish bucket filled with water and filter media. It's heavy. As another reviewer noted, I have to heave it out of the cabinet and haul it outside to maintain it.3. You may need to tinker with the selection and placement of filter media. A Google search will yield multiple hits from people who have suggestions and opinions on the topic. I may still be doing it wrong. From bottom to top I have a water polishing pad, two foam pads, and ceramic tubes. For some reason, the polishing pad gets saturated first, and ends up being the reason for reduced flow, while the others are only somewhat dirty. My tank is moderately planted, and I can go through perhaps 4-5 weeks between filter cleanings/media changes.4. You'll want a towel when disconnecting the filter from the hoses for cleaning. I have not found a way to keep about half a cup of water from escaping whenever I disconnect.5. It may take some elbow crease to depress the "buttons" (wrong term) to release the hose from the filter body. You have to depress them and lift the hose off, and sometimes it requires some effort.6. Expensive. It just is. That's a lot of money to drop on a filter. But I think it's well spent. I imagine you're paying for a powerful and well-built motor. No other piece of aquarium equipment (excluding the tank, of course) has lasted me 7 years - let alone in like-new condition. I feel that I easily have another 7-plus years out of it.Bottom line? I see no need to look for alternative filters for large tanks. I just bought a 300g aquarium, and when it arrives I will be furnishing it with another FX5 or FX6.