# Running Canister filters in series



## chiefroastbeef (Feb 14, 2011)

I don't have experience with this, but most people I have seen that uses a "prefilter canister" has the prefilter canister before the powered canister filter. To me, it makes more sense to have gravity pull the water down to the prefilter>powered filter, and then the motor/impeller immediately pushes the water back up.

I guess they call them "prefilters" for a reason.


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## madness (Jul 31, 2011)

My understanding of this is that you pull through the dummy canister or pre-filter/canister and then the powered canister pumps the water back to the tank.

So the canister that is turned on is second (or last) in line.

Shrimp breeders do this (primarily in Asia but also becoming popular over here for super expensive or sensitive shrimp).


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## willknowitall (Oct 3, 2010)

pre filter then powered filter


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## madness (Jul 31, 2011)

I am not sure if the finnex will have enough power/pressure to be used in this situation. Might need a canister with a pump which has some useful head pressure.

Unless the finnex is going to be the dummy/unpowered canister.


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## Nubster (Aug 9, 2011)

How about just using a canister like this as a prefilter? Or is that what you are talking about?


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## Naekuh (Oct 19, 2011)

if u had 2 canisters next to each other, each with a pump... cant you damage the impeller chamber by over working it?

Well in theory if u had enough restrictions where u would prevent the impeller spinning faster then it normally would... it would work, but the chance of over working your impeller could lead to premature failure no?


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## madness (Jul 31, 2011)

Yes, you could.

Liam uses some similar ones for fluidized bed filters.

There is no reason to waste an entire canister filter for a pre-filter if you have a simpler and cheaper option.



Nubster said:


> How about just using a canister like this as a prefilter? Or is that what you are talking about?


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## mordalphus (Jun 23, 2010)

The home filters like that don't hold much media, so they're not very good as a prefilter, they're great as reactors though.

You can also buy "dummy" canisters, which have no motor or anything, just an inlet in the top and an outlet at the bottom (think eheim style with no motor).

As far as damaging impellers, that would only happen if there was a pretty serious clog. Remember, gravity is pulling water down into the canister, the canister is only working to push the water back into the tank. Now if you did it backwards and had the canister in line before the prefilters, it would certainly damage the impeller if you could even get that situation to function.


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## Nubster (Aug 9, 2011)

You could probably DIY something from pvc and some hose barbs in that case couldn't you?


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## Tenor1 (Jan 15, 2012)

Years ago there was an external 3-stage canister filter system. I "think" the name was Jungle Life, or something close to that. I don't know if it's still available, but the concept could be copied.

My suggestion is to fully run the two canisters with one using mechanical media, such as sponges, and the other full bacterial media, hard surfaces. Use one spraybar horizontally and the other perpendicularly. That's what I do.


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## Rich Conley (Jun 10, 2008)

jack25 said:


> I want to run two canister filters in series. One will be powered and the other one is more or less just a container. The reason is to increase my options for filtration media. My question is should I put the powered filter first or second. First will be the suction side where the intake will be connected to the powered filter. If I put the powered filter second, the return to the tank will be connected to the powered filter. By the way I'm running a finnex 360. Thanks for any input. roud:


 
Put the powered filter first.


Centrifugal pumps do not like intake restrictions. At all. They push water, not pull.


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