# FX6 strikes again...



## LeeAberdeen

Just spent large chunks of a rare day off sorting out more problems with my FX6. When it works, the FX6 is a good filter, but blimey does it have design flaws. What's more surprising is that, if you Google it, they clearly had the same problems with the FX5, and it's STILL not been sorted. If you Google something like "FX6 trapped air" you'll see what I mean.

I swear that the last time it went wrong I hadn't even been near the thing, just came back from work and the familiar bang-bang-slosh-slosh noise has returned. So I switch it off and, ten hours later, it's back as it starts to increasingly gulp down air. Then it's down to eight hours, then six hours and yesterday, after a few switch-offs, TEN MINUTES. Very annoying, because the thing's in my front room and you can barely hear the TV above it.

Anyway, wanted to warn other people about the design flaw. Basically, the intake tube connection at the aquastop valve is a weak point. They've designed it in a really bad way so that the aquastop is difficult to remove and, during the manhandling this prompts, the connection loosens and begins letting in air. With me, about three or four removals of the aquastop for cleaning was enough to make it weak and, yesterday, it was leaking. This is in spite of me having two jubilee clips super-tight trying to hold it in place. I'm not even sure what use those clips are, because they're clamped around some rigid plastic which surely doesn't have any give to help them make the connection to the rubber bung firmer? And surely there's a better way to connect it on a £250 filter than a weak-fitting rubber bung?

As I said, this time it started letting in air I hadn't even touched it. It's like the thing is gradually weakening itself, probably because of the ridiculously short length of intake hosing they provide, which means it has to be stretched tight to fit over the back of your aquarium. My tank's only 18 inches tall, and if it was any taller I wouldn't be able to fit the FX6 at all because the hosing wouldn't stretch. It should be tight, yes, but not so tight that it's practically pulling the bung out. I can't see what's stopping them giving you a longer hose which you can then chop down to size, as with the outlet hosing? Surely a few extra inches wouldn't be critical to the filter working? Would it? Especially when it doesn't properly work now?

I have a second large filter on my all-male tank which cost a lot less than the FX6. I won't mention the manufacturer in case anyone thinks I have an agenda, but suffice to say it pumps almost as much water as the FX6 (about 2500 litres per hour), oxygenates my water better with its spray bar, is MILES easier to maintain, doesn't involve a wrestling match to disconnect it, has a larger media capacity and, crucially, doesn't bang and slosh at me if I fart in the wrong direction.

I'll never buy another FX6...


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## dledinger

In the mean time why not just put hoses to your liking on it? As far as the factory hoses, I have an intake at one end and outlet at the other end of a 125, and I had plenty of extra hose without stretching any and a couple feet to spare.

I'm new to the FX6...I've decided that I like it's function very much, but still hoping for the best with longevity.


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## LeeAberdeen

Not sure how you'd have "a couple of feet to spare" on the intake hose of an FX6 when the one supplied is about three feet long in total?

Hoses to my liking? What do you mean? The hoses supplied are to fit the FX6 and, as far as I know, they're unique to the FX6?


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## dledinger

LeeAberdeen said:


> Not sure how you'd have "a couple of feet to spare" on the intake hose of an FX6 when the one supplied is about three feet long in total?


That seems to be the misunderstanding, then. Mine came with several feet of hose. I'm using probably 6' on the suction and 6' on the discharge. So a good 12' plus the 3' or so I threw away in scrap.

I think you may have been shortchanged.

I'm not quite sure what you have going on with the clamps, either. They don't go around the corrugated plastic. As you know already, that doesn't work. They go around the rubber ends of the hose...and they shouldn't be death-grip tight.

I don't think these parts are made of the best of materials or most substantial design, but I really can't see them failing with such little service.


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## dledinger

Also, if you put a little crisco on the o-rings everything goes together and comes apart smoothly.


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## LeeAberdeen

Thanks. Not sure what "crisco" is, but if it's what we call vaseline, the FX6 instructions tell you not to use that on the O ring. They tell you to merely wet it. Never had a problem with the O ring, so I'm fine with that. My other big filter does tell you to use vaseline on the O ring though, so...

I have two FX6s because I bought a spare in case of problems, and both came with the same short length of intake hosing. The output hosing though, as you say, has plenty to spare. I'm not sure why there's that disparity.

I'm going to play around with the aquastop intake fitting because, looking online, the pdf instructions are different to the ones from the box. The ones I saw before didn't show the completed fitting, but the pdf ones say to push the bung "onto" the fitting, whereas mine are 'into' the fitting, which would explain why the clamps aren't working and why it's coming loose. It actually fits pretty snugly that way, but not for long.

Think you're right about the materials. I'd much rather have an Eheim for the build quality but, unfortunately, none of their models shift as much water as the FX6 and, as my turnover's about 9X and I'm striving for 10X, I don't want to lower that. I only have room for the fittings for two filters on my tank, so I'd rather go for bigger ones.

Thanks for your input.


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## dledinger

I hope you get it sorted out one way or another. I chose the FX6 for the same reasons as you. The Eheim is probably better built and probably a better bio filter, but I really wanted to move some water and appreciated the price of the Fluval.

Just a couple more comments...



LeeAberdeen said:


> Thanks. Not sure what "crisco" is, but if it's what we call vaseline, the FX6 instructions tell you not to use that on the O ring. They tell you to merely wet it. Never had a problem with the O ring, so I'm fine with that. My other big filter does tell you to use vaseline on the O ring though, so...


Crisco is vegetable shortening. I agree that you should shy away from petroleum products.



LeeAberdeen said:


> I have two FX6s because I bought a spare in case of problems, and both came with the same short length of intake hosing. The output hosing though, as you say, has plenty to spare. I'm not sure why there's that disparity.


Either we're far apart in interpretation of the instructions or we got very different things in the box. Mine came with two hoses: (1) drain hose, (1) continuous length of tubing to be used for both suction and discharge (needs to be cut in two). The diameter of the suction and the discharge should be the same.


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## LeeAberdeen

I get what you mean now. I'd actually bastardised my intake and used a 406 hose, hence the difference in widths. I'll fix that tomorrow with the full-width hose, which should help increase the turnover as well as eliminate the return of the sloshing noise. So that's doubly good news.

Either I'm a bit dense or the instructions weren't clear. It's probably a combo of both though...


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## dledinger

I pitched the instructions a few minutes in because I didn't understand them...so I'll err on your side


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## LeeAberdeen

You're very kind, so thank you. You've also been very helpful too, because I was dreading the return of the slosh and more cursing of Fluval. I should apologise to them, really, but I still think the FX6 could be a lot better (especially the instructions).


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## dledinger

I think you're totally right on the instructions, and I promise you, that's not just being kind. Even if it is the cheaper of the many solutions, the cost of a FX6 isn't targeted to someone toying around in the hobby. We deserve a bit better. I broke one of the "rim connectors" out of the box. The o-ring attachment felt a bit weak, so I wanted to try the suctions cups. Turns out I had it backwards anyway. But jeez, there's just no way to get that thing off the rim of a 125 without breaking it.

That said, as I mentioned above, I'm just getting started with this beast and _I want_ it to work. I want it to be a cost effective solution. I surely hope it works out that way!


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## LeeAberdeen

Those rim connectors are awful. Can't believe there's not a better way of connecting the lid than that. They look so flimsy, and whenever I look at my lid it's never fitting snugly, but sort of bulging like it's about to pop the connectors with all the pressure. If you loosen them off, though, you risk letting air in, so they have to be super-tight like that. Meanwhile, opposite my FX6, there's the much cheaper filter with the top sat on all neatly, and when you come to clean it, it lifts off easily, whereas the FX6 involves a feat of strength to remove the aquastop. I swear, if I was a little old man, I'd never be able to disconnect my FX6. It's an appalling design.


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## dledinger

Were you able to get this sorted out?


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## Deeda

I have the FX5 which has the same filter parts (except the drain hose) as the FX6 and the assembly instructions are identical between the 2 models in the user manual. I do have to comment that the instructions are some of the best I've seen for a canister filter.

First, the hoses must be installed onto/over the Aquastop valve and secured with the metal clamp. This prevents the hose from popping off, leaking or allowing air to enter.

Second, the rim connectors are the pieces that 'clip' onto the aquarium top frame and hold the intake and output hoses in position. I will concede that I had a great deal of trouble getting them to fit on my 125G tank with wide plastic trim and had to cut some of the plastic off the rim connector to use them.

To Lee, I'm sure the problem with air getting in to your filter is because you used the hose from the 406 filter model.

Also, removing the Aquastop valves from the filter lid connections shouldn't be that difficult, you need to squeeze the release clips and then lift up on the Aquastop valve to remove it. I recommend applying a bit of lube to the o-rings on the filter lid connections to allow a better release of the valves.

If the lid of the filter is bulging, something is not assembled correctly. Double check that you haven't added to much media to allow the trays to mesh correctly. You should not have to crank down the lid latches that tightly to secure it, over tightening the lid latches can deform the plastic and break things.


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## LeeAberdeen

Yes, sorted it. As always with the FX6 though, I hold my breath...

"Best... for a canister filter" is relative, though. If you're saying they're good instructions, there are at least two of us here who disagree.

There's hardly any filter media in because of the air problem, so it's nothing to do with that (which defeats the manufacturer's boasts about the great media capacity, too, when you can't use one of the so-called benefits of an FX6 in case it stops working). The lid doesn't sit snugly on the top, as it would do if it was well-designed, and loosening the nuts is likely to let air in.

On a further point of the poor design, when I last took the motor apart to get to the impellor for cleaning, the screw came away from its housing and I had to sort of tear the screw off. Mercifully, it did go back together but, again, it shows how shoddy the thing is. This is practically a new filter, and the impellor's been taken out twice, maybe three times most, so there's no excuse for that happening other than poor materials/design. It's a ridiculously complicated way of performing such a basic filter task as cleaning the impellor, and underlines how badly the thing is put together. Again, the much cheaper filter sat next to it comes apart easily and the impellor cleaning is simple. Take note, Fluval.

It's a recurring theme with them because, I note from googling, the 406 also has a design flaw which people have taken to fixing on the motor head's inlet valve. I just wish they'd test these things fully.


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## dledinger

Glad you got it working. Hopefully it stays that way a while.

I'm hoping I don't have to spend much time tinkering with the impeller or anything else for that matter. I know some people complain that it collects sand because of it's location.


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## Handyjoe

At my peak time, I have 10 of them, FX5 and FX6 combined. Sold a few tof them off. I now have 6 with two brand new ones still in the boxes. From my experiences, I think the FXs are the best filter. The small Fluval series are junk, IMO. I took everything apart to clean every few months. Never have a problem. Put it in after cleaning, turn on the valve and have it self-primed. Gotta love that part- no priming needed! Instructions? I have them both in CD and in small booklets. Never have to read them. Everything seems self explanatory.

Sorry to hear of your bad experiences. You may have a defective unit. Have you check all the o-rings? The inlet, outlet, and around the lid to see if they have seated properly?


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## dledinger

The instructions _aren't_ needed, which is my problem with them. 8 pages of information for what should be accomplished on one. They're just too long, drawn out and they unnecessarily complicate very easy things.

It would be far better if Fluval were to include a 1 page "quick start" guide (you know, like comes with everything these days).


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## JimA

Handyjoe said:


> At my peak time, I have 10 of them, FX5 and FX6 combined. Sold a few tof them off. I now have 6 with two brand new ones still in the boxes. From my experiences, I think the FXs are the best filter. The small Fluval series are junk, IMO. I took everything apart to clean every few months. Never have a problem. Put it in after cleaning, turn on the valve and have it self-primed. Gotta love that part- no priming needed! Instructions? I have them both in CD and in small booklets. Never have to read them. Everything seems self explanatory.
> 
> Sorry to hear of your bad experiences. You may have a defective unit. Have you check all the o-rings? The inlet, outlet, and around the lid to see if they have seated properly?


 I have to go with operator error here and probably like mentioned not the right hoses. I bought a FX5 used from a salt water guy for 75 bucks. Brought it home cleaned it really good, hooked it up (without instructions) not like it's rocket science, water in water out. The thing has been going for 3 maybe 4 years for me now. Only time I ever get an airlock or fine bubbles coming out of the return is when it needs to be cleaned. Next to some of the Ehiems they are arguably one of the best filters out there. All that being said glad you got it going, but no need to dis the product.


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