# Brand new Fluval 406 making rattling noise off and on



## Olivia23 (Jan 7, 2016)

I just received my new fluval 406 canister filter for my 55 gallon aquarium this past Saturday January 2nd. I took my time installing it since it was my first canister filter. I watched fluval YouTube video and read instructions so I'm fairly certain that it's installed correctly. Well the first day it runs perfectly and no noise. The next morning I wake up to a rattling noise but then it stops.

I drained all the water out, checked my impeller (everything looked fine) then put everything back making sure my impeller cover was completely shut and primed for several minutes to make sure all air was out. It ran fine for a few hours then started rattling again off and on.

I then stopped it, cut tubing so there was no slack at all then started up again. It ran fine for awhile then rattling noise again. I'm sick of it! I really want this to work! My water flow is fine during all this but I'm afraid all that starting and stopping will tear impeller up.

I bought this off amazon and unfortunately my husband threw my shipping box away. I guess I could get a new one but don't know how they would handle the return. Please advise me on what to do.


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## PogyKen (Jan 5, 2016)

Is the inlet sucking in air? Air in the impeller will make a rattling noise so if the inlet is near an airstone you can certainly have this happen. If this is the case I would move either the inlet or the airstone and then use the priming handle for 3-4 pumps.

Also with the Fluvals I have seen where the impeller is slightly pinched in its housing, it should spin freely (but not sloppy) when everything is assembled. The cap that snaps over the impeller can have a small bit or rubber in the hole that the impeller seats into, and if that is the case I have trimmed that hole just the tinniest bit so the impeller isn't binding on the rubber.

Hopefully one of those two helps you, I have had great luck with the Fluval canisters and find them to be a solid product once up and running.


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## somebody (May 13, 2014)

I'm 100.01% positive it is air and I don't recommend trimming the housing until all other methods are exhausted(including a faulty unit return)

When I ran mine I got the same thing. Just when it does that prime it using the plunger, while it's running, until the rattling stops. Air will get in there from time to time weather it was air being pulled into the line through weak connections of the rubber connectors to the hose or aqua stop valve. Bubble wands/stones close to the intake would do this as well as already suggested. So will not tight air seal between the pump head and media housing.

Air bringeth life, air taketh life


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## Olivia23 (Jan 7, 2016)

PogyKen said:


> Is the inlet sucking in air? Air in the impeller will make a rattling noise so if the inlet is near an airstone you can certainly have this happen. If this is the case I would move either the inlet or the airstone and then use the priming handle for 3-4 pumps.
> 
> Also with the Fluvals I have seen where the impeller is slightly pinched in its housing, it should spin freely (but not sloppy) when everything is assembled. The cap that snaps over the impeller can have a small bit or rubber in the hole that the impeller seats into, and if that is the case I have trimmed that hole just the tinniest bit so the impeller isn't binding on the rubber.
> 
> Hopefully one of those two helps you, I have had great luck with the Fluval canisters and find them to be a solid product once up and running.


I'm not sure what you mean by is the inlet sucking in air. The intake tube near the bottom of the tank and is sucking debrs correctly. The output tube is not above water. I also tried priming several times. I tried while the unit was running and it was rattling while I tried priming several times but it would not clear the air out. I primed while it was turned off and there was no air. just water pumping out.


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## Olivia23 (Jan 7, 2016)

Also there is no air stone or bubble wand near it.


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## areuben (Jul 17, 2003)

I am not familiar with Fluval filters however if you are confident there is no air, have you checked the impeller shaft - I know you said you checked the im peller itself, but did you take out the shaft - maybe defective?? hairline crack?? or some other defect?


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## nodima (Oct 3, 2002)

It's been a while since I ran a fluval filter, but I do recall that rattle happening. I suspect that some of those bubbles come from the sponges used in the filter - when they are rinsed they may retain some trapped air, which will slowly move to the impeller area, and sometimes does not get out the outlet.

I think this is a more likely culprit than a defective product.


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## Olivia23 (Jan 7, 2016)

Yes I also checked the impeller shaft, but when I go home I will check everything again. I did read the directions again online and found that they said to ensure a watertight seal, the cut end of the hosing, which connects to the intake assembly, must be kept under water. The cut ends on my intake and outake hoses I am pretty sure are both above water so maybe this could be it? I will make sure when I go home that both hoses where they connect with the intake tube and the output nozzle wll both be put below waterline just to make sure there is a watertight seal.

I really don't want to send this back, but I wished now I had bought an Eheim filter. If this does not fix the problem I wonder how Amazon will handle the return shipping since the Fluval is now used, full of water, and the hoses are cut? I am an Amazon Prime member and I order all the time off of there and have sent back a lot of items and never had any issues before. I did look up the return date on this order and Amazon says I have until February 2nd to return it.


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## somebody (May 13, 2014)

It doesn't matter to with the output, there is no vacuum draw on that side (only slight pressure),if it's a faulty connection between hose and intake tube putting it below the water line will help until the water level drops down to it. If it is determined that that is the culprit put a zip tie around it or a ss/ aluminum hose clamp to help seal the hose.

Another thing to check that is a common problem with first time users is the o ring that seals the head to the body. Vasoline helped my leaky filter but not likely the culprit here but worth a once over.

When you plunge the plunger dies it sound like sand going through? If so that's air not sand keep going till it stops. Try leaving it(the plunger) up and see what happens. I found by leaving it up the air tended to evacuate more better.

Try shaking and tapping on the housing to help release any air bubbles that may be trapped in your media.

Are you using the supplies ceramic rings that come with the filter? Those tend to trap air and take a little time to get it all out. Once they are "water logged" then they'll be good.


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## Olivia23 (Jan 7, 2016)

Okay I tried all these tips and nothing helps. I give up. I'm sending it back to amazon. I'm now looking at an Eheim or an Hydor filter. I have a 55 gallon so which would be the best?


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## somebody (May 13, 2014)

Olivia23 said:


> I'm sending it back to amazon.


Can't help on a brand but if they don't take it back I'll give you $100 for it 
Pm me if ya wanna sell it


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## Roger That (Aug 12, 2015)

My 406 has this same rattle at times but not too often. My FX6 is always quiet.


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## Scott Bryant (Sep 28, 2014)

when you took the lid off, was the impeller cover in place? I had a new one and the impeller cover kept coming off...bad fit. It would rattle a bit too but eventually the pressure would hold it in place. I bought a new cover that fit better and never had any more noise. For what it's worth, I had a brand new Eheim that I couldn't get to work for love nor money. I sent it back and got another Fluval 406. I have 3 of them and I like 'em.


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## Olivia23 (Jan 7, 2016)

I ended up sending back to amazon. Love them they are awesome on returns! I ended up ordering an Eheim classic 600. I got fed up with the Fluval and felt for a brand new item I should not have had the problems I did with it. I hope the Eheim is enough for my 55 gallon tank. I read that the eheim water movement is lower then what is listed.


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## nodima (Oct 3, 2002)

With canisters, there is a balance between media volume and throughput of water. Eheims IME do a good job of optimizing that balance. They are not the flashiest, wiz bang, feature filled, high numbers filter out there, but they are high quality, dependable, and do a great job. Don't get caught up in the "how much water the filter is pushing" frenzy.


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