# Canister Filter Help....Strange Noise



## DaveK (Jul 10, 2010)

In looking at your video, it seems there is air coming out of the return pipes.

This almost always means there is a leak on the intake side of the canister filter. You may not see any water because it's sucking in air at that point. This could also be the intake sucking in air bubbles. For example, if you have the intake over an airstone.

Recheck the intake side of your plumbing and the O ring used between the pump section and the base of the canister filter. Make sure nothing is damaged and all the connections are secure. Dirt on the O ring or the O ring being twisted can also cause leaks. A little lube on the O ring can help here too. 

If you just cleaned it, it is also possible that there is a lot of air in the canister base and the media in there. However, this usually goes away in time.


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## darkohanzo (Dec 21, 2016)

I had a similar situation but it was just that Oring around the top to the bottom of the canister wasnt seated in its channel properly so it didnt get a good seal which let alittle air seep it when it was running. Like DaveK said, just check all of your orings and make sure its still sealed up tight. Have you recently cleaned it or taken it apart?


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## RobnSonji (Oct 6, 2013)

It is sucking in air from somewhere.... either the intake hose or the lid to the canister. Somewhere on the IN side of things where there is negative pressure.

I have an FX6 that does that. The way the intake is designed there is a connection between two sections of tubing near the top of the aquarium. If I let the water evaporate down below that connection it sucks a tiny amount of air.


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## Daniel12490 (Jul 30, 2014)

I cleaned the filter about a month and half ago to two months ago. It seems to come in spells of making this noise to being perfectly silent and working just fine. I'll re-take it apart this weekend and investigate deeper. Thanks for the comments thus far everyone.


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## deeda (Jun 28, 2005)

I wish your video was a bit longer but meanwhile, unplug the filter and let any air trapped in the filter rise up through the output hose/pipe section. Wait 2 minutes and then plug the filter back in.

I agree with the others that you may be sucking air into the filter but it could also be something plugging the media or even the intake portion of the filter.

What other equipment do you have inline on this filter?


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## PlantGate (Aug 23, 2016)

This is why the FX5/6 pause every 24 hours to allow air to purge. If this is an ongoing issue I suggest you put this on a timer that shuts if off for 5 minutes once a day.


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## RobnSonji (Oct 6, 2013)

Daniel12490 said:


> I cleaned the filter about a month and half ago to two months ago. It seems to come in spells of making this noise to being perfectly silent and working just fine. I'll re-take it apart this weekend and investigate deeper. Thanks for the comments thus far everyone.


this sounds similar to my situation described above.....my spells of air came and went and it was driving me crazy as it was a brand new FX6. 

I would do a tank cleaning/water change and filter cleaning. All would be good for a few day. Then all the sudden for no apparent reason Id have air in my filter. Which was especially annoying because it is a FX6 and as was mentioned it is suppose to purge the air on its own.

There is a joint/connection in the intake tube near the top.
When I refilled the tank I would unknowingly fill it to a spot above that joint. After a few days of evaporation the water level would fall below that joint and it would suck air.


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## deeda (Jun 28, 2005)

I did comment on your journal thread but will do so again here.

Your DIY intake strainer doesn't have enough holes in it so you can either add more holes or you can buy a 1" to 3/4" PVC slip reducer and use the original Eheim strainer.


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