# Eheim Canister Filter, Slowed flow



## mott (Nov 23, 2006)

Try cleaning the impeller and check hoses make sure nothing is obstructing flow.
Do you have a pre filter sponge on the intake? They clog rather quick...


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## lauraleellbp (Feb 3, 2008)

It's normal for it to slow down *some,* but there may be something wrong if the flow is REALLY decreased from what it was...


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## vps (Apr 14, 2010)

The flow rate isn't a whole lot slower, but I would say it's noticeably slower. I haven't tried cleaning the impeller yet, does anyone know a good way to clean it?


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## lauraleellbp (Feb 3, 2008)

I use a bottle brush on my impellers and shafts.


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## dthb4438 (Nov 12, 2007)

I use a very small bottle brush. Also the hoses get "gunked" up quickly as well as the intake filter. Whenever my 2217 slows down in flow, it's usually the prefilter sponge that I have on to keep out the shrimp.


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## AquaDean (Nov 20, 2009)

I've noticed that my brand new Eheim 2211 had slowed to a crawl recently and it seemed like it was captivating air every so often. I kept checking and cleaning everything to no avail but then when re-assembling for the third time I inadvertently left out the bag of Purigen and the filter was instantly fixed. 

That of course leads to a question, It seems like the bag of Purigen sealed off the waters path to a crawl. When in the filter it forms a layer about an inch thick. Is this too much for the filter to suck the water through or do I need to find another way to put Purigen in the filter?


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## lauraleellbp (Feb 3, 2008)

What size bag are you using? If you're using the big 500mL you might try the 100mL bag instead.


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## AquaDean (Nov 20, 2009)

I'm using a Boyd's Chemi Bag and put about 200ml of the Purigen in it. This is a softer bag than the Seachem bags but does contain the Purigen. Being softer it conforms better to the shape that you want it to be, in the case of the 2211round and flat. I had set it up so that no water could bypass the Purigen. I'm now thinking that I might have put too thick of a layer of Purigen and will try to take half of it out and see what happens.


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## lauraleellbp (Feb 3, 2008)

Personally I've found Purigen to still be very effective even when water can bypass around it. I use the 100mL bags in most of my filters and though there is considerable area not covered, it still works very well. As long as you've got good tank turnover, I think that there really isn't a big loss in the long run.

I also have a friend who tried plumbing some bags of Purigen into some PVC pipes on his filter setup with the same goal of not allowing any bypass. The Purigen compacted and the bags ended up exploding from the pressure buildup, and made a royal mess.

I'd get a smaller bag.


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## stewardwildcat (Feb 24, 2010)

You cleaned it and replaced the blocked floss but over time gunk builds up on the top, in the impeller assembly, and even in the tubes. A pipe cleaner is fine but a toothbrush works too. I just took apart and cleaned a friends eheim last weekend. It wasn't too hard. Take the top (do not submerge it!) and take it to the sink. Be careful but in the intake area there is a flow meter for when the pump is trying TOO hard. Take that apart (it slides out of the shaft, assuming you have one) and be sure not to lose the parts. Rub the gunk off of all of the pieces and then scrub out the intake and outtake tubes. Once those are sort of clean turn it over and scrub the gunk off the bottom of the unit. Then take the plastic piece off that lies over the impeller. Now you can see how much buildup you have. Take the impeller out (it just rests in there) and scrub it down and be sure to clean out all of the crap that has built up in the place the impeller was. I noticed at least a millimeter of gunk that was surrounding the entire impeller hole and was slowing down the unit. Then put everything back together again and it should help.


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## chhabi19 (Feb 17, 2010)

Make sure the flow isn't reduced because of simpler things like:

1)Something with weight (like inline heater) pulling the outflow pipe downwards and squeezing the pipe somewhere.

2)Your inflow or outflow pipes are little longer than suggested. In that case, cutting them or sometimes moving the pipes in different angles helps the flow.

How do I know it? Experienced both of them :hihi:


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