# Placing intake/outflow pipes at opposite ends of tank



## jbig (Jul 13, 2012)

I just got my new mr aqua 12g long set up and running. 



I also purchased an eheim 2213 canister filter for it. I decided to place my outflow and intake pipes at opposite ends of the tank but noticed that many people place them on the same side of the tank. 



Are there benefits/disadvantages to doing this? I figured i could get better flow placing them at opposite ends but maybe i dont quite understand how flow works in the tank yet. Or maybe it doesn't even matter? 



Opinions appreciated! 




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## bsantucci (Sep 30, 2013)

jbig said:


> I just got my new mr aqua 12g long set up and running.
> 
> 
> 
> ...


Correct placement is on the same side as far as I know from my readings and personal usage. the idea is you want a nice laminar flow from side to side bringing all the garbage in the water column and substrate all to one side. I think having the intake on the opposite side would stop the laminar flow also so you wouldn't have good circulation.


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## jbig (Jul 13, 2012)

bsantucci said:


> Correct placement is on the same side as far as I know from my readings and personal usage. the idea is you want a nice laminar flow from side to side bringing all the garbage in the water column and substrate all to one side. I think having the intake on the opposite side would stop the laminar flow also so you wouldn't have good circulation.


Even on a 3ft tank? My concern was that the outflow wouldn't reach far enough across the tank to have it bounce back. I also have heard that many people have flow issues on this tank which is another reason i wanted to try something different. 

When i first got everything up and running yesterday i turned on my co2 and the mist that came from the outflow (using inline diffuser) was coming out pretty strong. From what i could see, the co2 was being dispersed relatively evenly. I'll pay more attention when I get home from work tonight though. I think the only possible dead spot would be in the back left corner below the outflow pipe.


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## bsantucci (Sep 30, 2013)

My tank currently is 3 foot and heavily planted. To remedy the flow not making it back across I installed a powerhead on the far side to push the flow back.

It really depends on how your tank layout is and you may have to play with it a bit. Correct placement is definitely on the same side though.

I'm setting up a new Mr. Aqua 48g which is 3 foot also but I'm doing Iwagumi style this time so I don't anticipate needing the powerhead since I will only have carpeting plants on majority of the far side, not as much stopping the flow like my current tank.


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## jbig (Jul 13, 2012)

bsantucci said:


> My tank currently is 3 foot and heavily planted. To remedy the flow not making it back across I installed a powerhead on the far side to push the flow back.
> 
> It really depends on how your tank layout is and you may have to play with it a bit. Correct placement is definitely on the same side though.
> 
> I'm setting up a new Mr. Aqua 48g which is 3 foot also but I'm doing Iwagumi style this time so I don't anticipate needing the powerhead since I will only have carpeting plants on majority of the far side, not as much stopping the flow like my current tank.


I'd like to keep all my plants relatively low in the tank. I already have a heavily planted 20g long jungle and I want something a little less hectic with this set up. 

Mainly doing carpeting plants with some taller background plants at the edges. 

I'll fiddle with the pipes a bit when I get home. Buying a powerhead was an option i considered but i'm trying to keep equipment numbers as low as possible.


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## creekbottom (Apr 5, 2012)

I think the main reason for having in and out on the same side of the tank is to help bring detritus back to the filter. Whether you are using a spray bar or a jet output it will most likely shoot across the top of the tank, it hits the far side of the tank and curves downward to sweep across the substrate (picking up gunk) and bringing that gunk to the filter.

I think the way you have it set now you may not be getting that water motion over the substrate.


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## bsantucci (Sep 30, 2013)

If you find that you need a powerhead, go for a koralia nano. I run a nano 240 in my 46g bow front and it helps bring the flow back across keeping everything laminar. The bonus is that the nano agitates the surface a bit for me. I also have and tried a nano 425 but it was a bit too strong for my tank.


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## lauraleellbp (Feb 3, 2008)

Part of the benefits of running a canister filter is that you can customize so much to the needs of your particular tank.

Position them however works best with your particular hardscape, softscape, and fish.


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## Smeagol (Mar 4, 2013)

I have an Eheim 2217 with intake and outflow at opposite ends of a 55 gallon (4 foot) tank. I did not know that having the intake and outflow on the same side is the "correct" setup. I don't think I have any dead spots. All my plants sway gently, and the CO2 bubbles coming out of my spraybar disperse all through the tank. I have the holes on my spraybar aimed slightly downward so that the CO2 bubbles get blown through all levels instead of just staying near the top. Maybe someday I'll move the intake and outflow to the same side to see what difference it makes.


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## jbig (Jul 13, 2012)

creekbottom said:


> I think the main reason for having in and out on the same side of the tank is to help bring detritus back to the filter. Whether you are using a spray bar or a jet output it will most likely shoot across the top of the tank, it hits the far side of the tank and curves downward to sweep across the substrate (picking up gunk) and bringing that gunk to the filter.
> 
> I think the way you have it set now you may not be getting that water motion over the substrate.


this does seem to be the case. I paid closer attention to the flow in my tank when I got home last night. Even though there was a pretty steady flow throughout the tank, when I moved the intake to the same side as the outflow, the flow along my substrate seemed to increase pretty noticeably. 




bsantucci said:


> If you find that you need a powerhead, go for a koralia nano. I run a nano 240 in my 46g bow front and it helps bring the flow back across keeping everything laminar. The bonus is that the nano agitates the surface a bit for me. I also have and tried a nano 425 but it was a bit too strong for my tank.


thanks bsantucci, koralia is actually what i was looking at and seem to have a great reputation on here, they have been recommended to me before. thanks for all your input. 



lauraleellbp said:


> Part of the benefits of running a canister filter is that you can customize so much to the needs of your particular tank.
> 
> Position them however works best with your particular hardscape, softscape, and fish.


this is my first time using a canister filter and I must say i'll never go back to a HOB. 



Smeagol said:


> I have an Eheim 2217 with intake and outflow at opposite ends of a 55 gallon (4 foot) tank. I did not know that having the intake and outflow on the same side is the "correct" setup. I don't think I have any dead spots. All my plants sway gently, and the CO2 bubbles coming out of my spraybar disperse all through the tank. I have the holes on my spraybar aimed slightly downward so that the CO2 bubbles get blown through all levels instead of just staying near the top. Maybe someday I'll move the intake and outflow to the same side to see what difference it makes.


I tried switching it up last night and even though it seemed that i was obtaining pretty good flow with the pipes on opposite ends of the tank, when I put them on the same side it definitely seemed to increase flow near the substrate. 

In all honesty, I tried to make the perfect set up when purchasing equipment for this tank. Many people seem to use eheim canister filters on these 12g long tanks so thats what I decided to go with. But I can't for the life of me figure out why so many people have flow issues on these tanks. This canister filter does and awesome job without need for a powerhead IMO roud: but i guess i'll give it a month and see how everything turns out before i make any more assumptions.



thanks for all the input everyone. much appreciated.


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## AGUILAR3 (Jun 22, 2013)

> I did not know that having the intake and outflow on the same side is the "correct" setup.



Interesting. I did not know that either.

I always thought that keeping the intake and outflow on the same side wasn't such a good idea because you would basically be filtering filtered water. I figured that if put on opposite ends of a tank, the water being filtered(outflow) would have to travel the whole length of the tank to get to the intake.....However, now that I think about it, I did notice that what little duckweed and floaters I have, they always end up on near the HOB filter so I know for a fact that even when placed on same side (input/output), there is still flow on the opposite end of the tank.


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## lauraleellbp (Feb 3, 2008)

jbig said:


> But I can't for the life of me figure out why so many people have flow issues on these tanks. This canister filter does and awesome job without need for a powerhead IMO roud: but i guess i'll give it a month and see how everything turns out before i make any more assumptions.


Flow will reduce dramatically over the coming months as the filter becomes established and starts to collect mulm.

Also, many people run inline CO2 reactors and such that can dramatically reduce flow.


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## creekbottom (Apr 5, 2012)

All those pesky plants that everyone is always yammering on about get in the way of the water as well. roud:


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## H2Ogal (Apr 27, 2010)

Well, count me in the "incorrect" column as well. Not only are my intake and outflow on opposite sides, but I also have lots of those pesky plants that creekbottom mentioned getting in the way.


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## Steve002 (Feb 7, 2014)

Researching what folks had to say about ideal water flow I went with across the top, down the front, across the substrate to the back again. I have a 36 x 12 x 21H tank and use 2 Ehiems 2213's and an external 570 gph pump used with the inline CO2. All my intakes/outflow pipes are on the back.
You will probably find you'll have to supplement the flow on the 2213 since they aren't strong.


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## jbig (Jul 13, 2012)

lauraleellbp said:


> Flow will reduce dramatically over the coming months as the filter becomes established and starts to collect mulm.
> 
> Also, many people run inline CO2 reactors and such that can dramatically reduce flow.


that's what i figured. perhaps, over time, i will be looking at getting a powerhead.

even so, I have an inline hooked up to my outflow and it still seems rather strong.


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## jbig (Jul 13, 2012)

creekbottom said:


> All those pesky plants that everyone is always yammering on about get in the way of the water as well. roud:





H2Ogal said:


> Well, count me in the "incorrect" column as well. Not only are my intake and outflow on opposite sides, but I also have lots of those pesky plants that creekbottom mentioned getting in the way.


Who do those plants think they are anyways? Can't boss me around. Hopefully my "mostly carpeting plants approach" takes care of that issue. 



Steve002 said:


> Researching what folks had to say about ideal water flow I went with across the top, down the front, across the substrate to the back again. I have a 36 x 12 x 21H tank and use 2 Ehiems 2213's and an external 570 gph pump used with the inline CO2. All my intakes/outflow pipes are on the back.
> You will probably find you'll have to supplement the flow on the 2213 since they aren't strong.



so far so good, even with the inline attached. I'll keep an eye on it over time though and eventually I will probably take bsantucci's advice and pick up a koralia powerhead. As for right now, I see my co2 being dispersed evenly and rapidly enough after putting my pipes on the same side.


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## beedee (Jul 1, 2010)

I have a 12g Long, and am using a 2213. Pipes are mounted next to each other at the left end of the tank, double-taps are all the way open on the outflow and i have great circulation. The outflow is angled almost at a 45˚ angle towards the front wall of the tank. I have a dense portion of Rotala Indica, Stargrass and Sunset Hygro at the far right side and along the back wall of the tank and the water still continues to flow in a nice and steady counter-clockwise direction.

My co2 diffuser is nearly under the outflow, just slightly to the left of it, so the flow carries the bubbles into the path of the outflow and they are dispersed though out the tank.


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## BeastMaster (Dec 17, 2012)

jbig said:


> I just got my new mr aqua 12g long set up and running.
> 
> I also purchased an eheim 2213 canister filter for it. I decided to place my outflow and intake pipes at opposite ends of the tank but noticed that many people place them on the same side of the tank.
> 
> Are there benefits/disadvantages to doing this? I figured I could get better flow placing them at opposite ends but maybe I dont quite understand how flow works in the tank yet. Or maybe it doesn't even matter?


Aloha jbig. Like you I'm running a 2213 on my 12L. I do have both intake & output pipes on the same side and have installed my CO2 inline atomizer on the intake side. My plant (HC only) & hardscape layout (low scattered seiryu stones) provide an unobstructed water flow pattern.

While observing the pearling & CO2 micro bubbles, I can see that the water flow is strong enough to reach the other end of the tank front and circle back to the back rear where the intake is located. This occurs with the output double tap closed off 40-45%! At least with my set up, the 2213 is more than adequate to create a complete circulation pattern (see "Kahawai" tank journal).

With that said, IMHO your aquascape layout should dictate your pipe placement (see "Iwagumi 60" tank journal). Pick your pipe locations and let it run for a while. Observe telltale signs of circulation patterns & possible dead spots. Watch plant growth patterns. If your plants are not responding to the circulation pattern or mulm/debris seems to be collecting in undesirable spots in the tank, move the pipe(s). Hope that helps & good luck! :bounce:


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## Smeagol (Mar 4, 2013)

I notice that a lot of Eheim users have their outflow/spraybar attached to the back of the tank so that the current flows toward the front of the tank. But I have my spraybar attached to the left end of the tank so that the current flows left to right. I don't know if this makes any difference as to whether or not I should move my intake to the same side as my outflow. I guess I'll just have to try it and see what happens.


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## Calbears (Mar 1, 2014)

FWIW I have an Eheim 2213 and have the intake and spray bar on the right side. The spray bar is pointed slightly up and to the left. I placed the co2 diffuser at the bottom of the left side with a koralia nano above it (pointing down and to the right). The flow in my 36g seems just about right.


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## Smeagol (Mar 4, 2013)

The curiosity was killing me, so I moved the intake of my Eheim 2217 to the left end of the tank. Now the intake and the outflow (spraybar) are both on the same side. To be honest, I can't really tell much difference. My plants might be slightly more upright, maybe. But I don't observe any major changes in flow. The areas that had a lot of current before the change, still have a lot of current. And the areas that had little current before, still have little current.


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## jbig (Jul 13, 2012)

BeastMaster said:


> Aloha jbig. Like you I'm running a 2213 on my 12L. I do have both intake & output pipes on the same side and have installed my CO2 inline atomizer on the intake side. My plant (HC only) & hardscape layout (low scattered seiryu stones) provide an unobstructed water flow pattern.
> 
> While observing the pearling & CO2 micro bubbles, I can see that the water flow is strong enough to reach the other end of the tank front and circle back to the back rear where the intake is located. This occurs with the output double tap closed off 40-45%! At least with my set up, the 2213 is more than adequate to create a complete circulation pattern (see "Kahawai" tank journal).
> 
> With that said, IMHO your aquascape layout should dictate your pipe placement (see "Iwagumi 60" tank journal). Pick your pipe locations and let it run for a while. Observe telltale signs of circulation patterns & possible dead spots. Watch plant growth patterns. If your plants are not responding to the circulation pattern or mulm/debris seems to be collecting in undesirable spots in the tank, move the pipe(s). Hope that helps & good luck! :bounce:


I now have my pipes on the same side. I have mostly carpeting plants (micro sword in the center of the tank, s. repens at the front edges, wisteria in the back right, telanthera cardinalis back left) so my flow is virtually unobstructed. Outflow pipe is in the front left flowing from left to right, intake is now on the back left. I have my double taps open all the way but I may tone it down a bit when I add fish. Everything seems to be going according to plan. 



Smeagol said:


> The curiosity was killing me, so I moved the intake of my Eheim 2217 to the left end of the tank. Now the intake and the outflow (spraybar) are both on the same side. To be honest, I can't really tell much difference. My plants might be slightly more upright, maybe. But I don't observe any major changes in flow. The areas that had a lot of current before the change, still have a lot of current. And the areas that had little current before, still have little current.


I didn't notice a drastic change (if any change) in flow along the top. But i will say that i can see flow along the bottom near the substrate moving noticeably quicker. I'm sure that would vary from tank to tank though.


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## TekWarren (Oct 6, 2013)

AGUILAR3 said:


> Interesting. I did not know that either.
> 
> I always thought that keeping the intake and outflow on the same side wasn't such a good idea because you would basically be filtering filtered water.


This would only be the case if you somehow managed to to point your outflow directly at your intake. Having the intake and out flow in the same corner (with the return pointed away from the intake an any direction) actually ensures that the filtered water circulates as much as possible before re-entering the filter. At least that is the theory.


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