# Cannister Filters in Series



## sevo88 (Jun 30, 2004)

I have a 150 L planted tank with Eheim 2222 (500L/h). I want to add an external CO2 reacter and a chiller and worry that the filter flow will not be sufficient. I want to avoid too many hoses in the tank and therefore am thinking of adding a Eden 501 (300 L/h) in series before the Eheim. I shall feed CO2 into the inlet hose and use the Eden as CO2 reactor. 

Can the group advise me whether the idea is sound? What are the effects of arranging two filters in series ? Any potential problems, particularly leak, airlokc and noise? Will the flow be 300 L/h, 500 L/h or 500-800 L/h?

Many thanks in advance.


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## gnatster (Mar 6, 2004)

In effect you would be putting pumps in series...

From Aquatic Systems Engineering by P.R Escobal



> Suppose pump 1 has an input pressure of of 5 PSI and devolop a relative pressure of 8 PSI. It therefore inputs water at 13 PSI. But if this water is fed into the intake of pump 2, the pressure will be raised by the realitive pressure of pump 2, e.g.. if pump 2 has a relative pressure equal to pump 1, namely 8 PSI, then the new pressure at the output of pump 2 will be 5+8+8=29 PSI. Elevated pressures are often desired for the purpose of raising water to heigher elevations. However, one must keep in mind the pump seals, basicaly the "O" rings can only resist an upper pressure limit and the seals may buckle if three or four pumps are connected in series.


In your example of placing 2 cannisters in series keep in mind that the second one can only pump as much as the first can push out. So if you place a 300L/h cannister inline before a 500L/h one the second one can only flow as much as the first. It will however raise the pressure at the return being the intake is at a greater pressure then if not in series. I would think this may tax the seals of cannister # 2. Placing the higher flow one first may cause issues as well. The restriction of the lower rated one may tax the motor and place undue pressure on the return line out of the first. What may be a better approach is to have seperate drain lines to each cannister and one return connected with a "Y". Using a "T" as oppsed to a "Y" may cause issue with the more powerful of the 2 pushing against the other where a "Y" will allow them to blend.


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## 83mulligan (Dec 28, 2004)

*recirculation pump*

Why not just buy a recirculation pump and pump the flow up through a diy canister packed with filter floss and bio material and then back down through a diy co2 reactor, then return to tank? I've been researching this a little and think it would work fine. I even plan to do this with the heater inside the diy canister and have nothing in the tank besides intake and return lines. Anyone have any comments on why this would not work?

Thanks,


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## gnatster (Mar 6, 2004)

> Why not just buy a recirculation pump and pump the flow up through a diy canister packed with filter floss and bio material and then back down through a diy co2 reactor, then return to tank?


Thats an alternative, as would using a sump. All would attain the same goals, only using different methods. Also not everyone is at the same comfort level when it comes to DIY projects.


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## 83mulligan (Dec 28, 2004)

*In line cannister filter*

Gnaster,

Feeding water in the bottom and out the top, with 1" infeed and discharge and a 5" cylinder, what thickness of filter floss and biomedia would you reccomend? I may upgrade the tank to 85 gallons and try to establish an outflow rate at tank discharge of 350 gph.

Thanks for your comments.


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## gpodio (Feb 4, 2004)

I would T off both the intake and return hoses and place the second pump and accessories in parallel to the existing canister filter. This way you are still using the existing tubes in the tank but not effecting pressure levels in the canister.

Hope that helps
Giancarlo


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## sevo88 (Jun 30, 2004)

gpodio said:


> I would T off both the intake and return hoses and place the second pump and accessories in parallel to the existing canister filter. This way you are still using the existing tubes in the tank but not effecting pressure levels in the canister.
> 
> Hope that helps
> Giancarlo


This is a very good idea. I shall take your advice.

Thanks, group.


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## Firethorn (Aug 2, 2006)

I heard that the eden has a sensor that will release any gas in the canister..

that's just me though.. may have misunderstood..


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