# Side by side planted tank as filter?



## emptyhead (Apr 16, 2007)

I have two 150g tanks that are in a corner. One is a planted community tank and the other is an overstocked mbuna tank.

I have been thinking of using the planted tank to help filter the other tank. They both have FX5 filters. My first thought was to switch the outputs to move the water from one tank to the other, but I'm sure that the two filters do not have identical flow rates - so that won't work.

Is there any way to turn my two closed systems into one system?


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## Rhinox (Sep 10, 2009)

If you switch the canister outlets, just get a siphon tube set up between the 2 tanks so any flow imbalance just goes through the siphon.


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## emptyhead (Apr 16, 2007)

Rhinox said:


> If you switch the canister outlets, just get a siphon tube set up between the 2 tanks so any flow imbalance just goes through the siphon.


Really - that would work? Where do I set that up? Out of the top of the two tanks or do I need to drill?

I may have to set up a test case.


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## emptyhead (Apr 16, 2007)

double post


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## emptyhead (Apr 16, 2007)

double post


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## kmuda (Nov 27, 2009)

I think the best way of accomplishing this is via a shared sump, with overflow boxes on both tanks and two return pumps in the sump, one for each tank.


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## Rhinox (Sep 10, 2009)

yeah it will most definitely work. All you need is a tube full of water between the 2 tanks, and the siphon will work to keep the water level between the 2 tanks equal. You can use a length of tubing, or construct a more rigid siphon out of pvc, or I suppose you could drill and run tubing under the tanks and keep it more out of sight.

One thing to consider - if one of your filters suddenly stopped working, make sure the siphon is large enough to handle the entire flow of one filter, otherwise you risk emptying one tank while flooding the other all over the floor.


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## kmuda (Nov 27, 2009)

Correct me if I'm wrong.... It will work if the tanks are the same height. Just a quarter inch on one side will throw the hole thing off. In other words, even if the tanks are the same height, the floor better be level.

Whereas, if both are operating independently of the other but sharing a common reservoir of water, it's a not a concern.


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## emptyhead (Apr 16, 2007)

Interesting thoughts.

The tanks are sitting on the floor in a church nursery. The two filters are stuffed in the corner between the tanks. The filter intake and output are on one end of the tank. The tanks are viewable from both sides and one end. I will try to get some pics to show the setup.

I'm not sure that I can run a sump with the current setup.


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## Toby_H (Apr 15, 2005)

Yes it is possible, and I think it's a GREAT idea... but you had better think it all the way through...

As Kmuda suggested, one approach is a shared sump. If both tanks are filter via sump now then I encourage following that apporach. But there are other options...

Sharing cansiters is (in my opinion) asking for trouble. If one filter clogs or dies, then the siphon is forced to attempt to move the full volume the remaining canister is moving. Two bodies of water at nearly the exact same elevation will not produce a fast moving siphon.

My suggestion is to use a small powerhead to move water from one tank to the other. 50 gph will cycle the full volume of one tank into the other in 3 hours which should be more than enough to acheive your goal.

Use multiple siphon pipes to counter balance the water moved by the powerhead. Keep in mind that a siphon between two bodies of water that are at equal elevations will move extremely slow. Technically if both bodies of water are at equal elevations the siphon will not move at all. One body of water will need to be at least slightly higher than the other...

You will also want to use a fail proof siphon. Illustrated here:










If you drain water from one tank (example: water change) the water level of both tanks will drop... until the water level of the tank falls below the top of the upward facing pipe. Then the other tank and the siphon pipe will remain stagnant until the tank is refilled...

You will still need to ensure the siphon doesn't take in bubbles and allow them to collect in the siphon.

For reference, I have used this system in my own home and it worked like a charm... here is my set up...

Here is an illustration to give you the concept...










Here is the real deal to prove I really made it 










The center tank is a 75 gal... each (top and bottom) 75 gal has a small powerhead that pushes water through a T and to each 10 gal (left and right)...

I used three 3/4" (ID) PVC pipe siphons to balance the flow... each PVC siphon had a sponge prefilter over it...

I used this system to plumb my fry tanks (10 gal) to the breeding tanks (75 gal). This prevented me from the chore of daily water changes on the fry tank but gave me the benefit of ner perfect water parameters.


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## kmuda (Nov 27, 2009)

It would certainly be difficult to run a sump if the tanks are on the floor, not safely anyway. The only necessity is the sump (water reservoir is a better description in this case) be lower than the main tank and gravity will do the rest. A 5 gallon bucket could be used as the common water reservoir. The problem with that is you don't have any room for error (say... a power outage or a return pump fails), in which case the 5 gallon bucket overflows.

However, if you "seal" the bucket, you could limit that problem. A bucket with a sealable lid, bulkheads for the inflow and return tubes, and flood worries are much minimized, if not eliminated.

Actually, as I typed this, I was designing it in my head. I might have to build one. :lol:

Let's see.... bucket, vinyl tubing, appropriate barbed fittings (threaded to barbed), PVC disconnects (so you can easily disconnect everything for cleaning), threaded bulkheads.... and I'm there. :thumb:

EDIT... Toby_H posted while I was typing. I like the concept and it solves my concerns of the tanks being level as it's the water level... that is level. Lots of loss brain cells but it (the brain) still works. :thumb:


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## emptyhead (Apr 16, 2007)

Okay - I think I kind of get Toby's multi siphon system.

The issue is enough siphon to compensate for the powerhead flow.

Either way - it all scares me.


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## kmuda (Nov 27, 2009)

Provided the PVC pipe is large enough, it should not be an issue.


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## Toby_H (Apr 15, 2005)

emptyhead said:


> Okay - I think I kind of get Toby's multi siphon system.
> 
> The issue is enough siphon to compensate for the powerhead flow.
> 
> Either way - it all scares me.


Risk comes in two ways with a system like this, 1) siphons not keeping up with the pump, or 2) siphon tubes/pipes loosing siphon.

Keeping the flow between the tanks very slow will reduce the flow the siphons are requires to maintain. Which is why I am suggesting a small powerhead as opposed to a canister filter.

Using the 'fail proof' or 'self starting' siphons illustrated above will greatly reduce risk as they will hold a siphon during a water change. I often end up with a lot dgoing on during a water change and it's too easy to forget somethign simple like restarting a siphon. Which is why I just love that design as the siphon starts itself.

When refilling the tanks, I can watch water "rush" through the siphon at a force that is more than enough to push any air bubbles that may have collected in the pipe into the other tank... Having used this application on a number of set ups, I consistently find that I have no air bubbles in the pipe. As long as the PVC siphon doesn't leak (let air in), and there is no bubbler near the siphon, then there is simply no air under water to collect in the pipe.

In my case the biggest risk is a friend tinkering with something when I'm not looking.

On my set up described above I found that one 3/4" ID PVC siphon could almost keep up with my small powerhead. Therefore I used three 3/4" ID PVC siphons.

If you are considering it but are nervous, I suggest you tinker with the idea in a more controlled environemnt. Make some siphons as illustrated above, grab some tupperware bowls and take a bath.

Such a set up will not be worth it if you lay awake in bed all night wondering...


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