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Discussion Starter · #1 ·
Canister filter have to be middle or can it be on the side with long hose/short hose?

I normally seem them setup with the canister filter in the middle under the aquarium in the middle however I have an aquarium without access to the bottom of the cabinet so the only possible place I could place a canister filter would be to either side of the aquarium.

If I did have the canister filter on one side, I might have to have 1 long hose(perhaps the water intake hose) all the way to the opposite side of the tank then the water hose perhaps being the short hose( perhaps so the pump won't have to pump the water as far)?

Does anyone know if this will be ok or if there is a reason this should not be done?

Thanks
 

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I've run mine in the past w/ a long hose/short hose setup. Sometimes you don't have much of a choice. My 10 Gallon I had was on a counter so the canister had to sit beside it. When I had my 40B I had the canister out to the side a lot because of easier cleaning.

And the pump should work regardless of where it is pushing the water to or from. I will say I've always gone the inlet side for short giving me more freedom with the spray bar placement.
 

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Won't matter much . What matters is the head height , i.e. how far up the water needs to be pumped . Pumping from the canister to a tank on a normal height stand won't be an issue . Canister on the floor pumping up to the top tank on a 3 tier rack could well be.
 

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Discussion Starter · #6 ·
Won't matter much . What matters is the head height , i.e. how far up the water needs to be pumped . Pumping from the canister to a tank on a normal height stand won't be an issue . Canister on the floor pumping up to the top tank on a 3 tier rack could well be.

If the canister is in the stand or on the floor maybe almost no difference on how high it is. The stand height is only as thick as the wood on the bottom floor piece which is maybe an inch or something.

Do you know which hose should be the long vs short hose?

The intake(siphon) or the return water(connected to the pump I assume)

Thanks
 

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I have my intake and output on the same end. The return to the tank (spray bar) is near the top directed across the surface somewhat with the flow the long way across the tank. The filter intake is below it near the bottom and I seem to get a nice circular flow across the top and then back again across the bottom. As the filter is located near the same end both hoses are pretty short. If you are going to have one hose longer than the other I agree the return to the filter should be the longer of the two.
 

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Discussion Starter · #9 ·
I have my intake and output on the same end. The return to the tank (spray bar) is near the top directed across the surface somewhat with the flow the long way across the tank. The filter intake is below it near the bottom and I seem to get a nice circular flow across the top and then back again across the bottom. As the filter is located near the same end both hoses are pretty short. If you are going to have one hose longer than the other I agree the return to the filter should be the longer of the two.
Will a longer return hose street the motors more to be pumping the water a greater distance?

The siphon will just use gravity and suction from water following water down the hose.

If this is the case, why would it not be better to have gravity move the water the greater distance and have the pump move the water up the shortest distance?

Thanks.
 

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Will a longer return hose street the motors more to be pumping the water a greater distance?

The siphon will just use gravity and suction from water following water down the hose.

If this is the case, why would it not be better to have gravity move the water the greater distance and have the pump move the water up the shortest distance?

Thanks.
Not sure about fluid mechanics but the explanation using basic physics (newtonian mechanics?) would explain your question. The only force acting against the flow of water is gravity and gravity only acts in the vertical direction (height). Thus lateral movement can be neglected since no lateral resisting forces are present. All other forces would be equal since its the same exact hose and would have the exact same fittings either way. Even if some other force is present, I'm sure it's small enough that for our purposes it can be negleted.
 

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Won't matter much . What matters is the head height , i.e. how far up the water needs to be pumped . Pumping from the canister to a tank on a normal height stand won't be an issue . Canister on the floor pumping up to the top tank on a 3 tier rack could well be.
There is an "opposite" problem as well.. Canister head usually needs to be lower than the tank rim (more correctly, water line)..sometimes by a few inches..

you actually have more "headroom" below the tank than above the tank..
 

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For my ehiem 2232 it didnt matter. I did have the intake at one end and the out at the other end and my caniser was on the side of my tank with no issue. I have tried swapping both and had no issues.

Right now my short tube is on the intake and long tube on the outtake and both are on the right side, still no issue. Have a circulation pump on the left side to circulate the water in a clockwise motion. This also helps diffuse more co2 before actually entering the tank.
 

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Once the pump start's the flow of water into the filter, gravity takes over just like syphoning water from a hose.
Pump does not have to work all that hard after that.
If you fill the hose that draw's water from the tank (close the valve on end of hose) when priming the filter ,you see how gravity work's when the water rushes into the filter when you hook up the hose and open the valve.
Pump only need's to start the syphon .
Doesn't really have to pump too hard after that due to gravity.
 

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Not sure about fluid mechanics but the explanation using basic physics (newtonian mechanics?) would explain your question. The only force acting against the flow of water is gravity and gravity only acts in the vertical direction (height). Thus lateral movement can be neglected since no lateral resisting forces are present. All other forces would be equal since its the same exact hose and would have the exact same fittings either way. Even if some other force is present, I'm sure it's small enough that for our purposes it can be negleted.
From my experience designing sprinkler systems I can tell you there is another factor working against the flow of water. It is the resistance of the water flowing through the pipes, tubing, fittings, anything it passes through. The result is pressure loss. This is figured just as pressure loss due to increase in elevation is. In this application it is probably so little it's not a real factor at all but it still is better to have the pump move the water through as little of this resistance as possible.
 

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Jr is right. There are a few things at work here. "Head" doesn't really apply, as a canister filter is a closed system, unlike a sump, where head matters a lot.
Increasing the vertical distance between the aquarium surface and the canister filter will increase (positive) pressure on the seals, which can lead to leaking, and it will lengthen the hoses, which increases resistance/friction as described above. You will notice that resistance when blowing through a garden hose to empty it.
Depends on the pump, but many impeller pumps work better pushing water than sucking it. So I think in many cases having a longer outflow and a shorter inlet beats the opposite. Otherwise, "cavitation" can occur. It's something you can try though - some canister designs behave differently than others, depending on the location of the motor etc.
 

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From personal experience the question is not can it be done but should it be done.

The more direct path straight down to the filter, with the shortest hose possible, will create the greatest flow.

The less direct the path, the greater loss of flow.

What is acceptable is up to you.
 

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Discussion Starter · #17 ·
Once the pump start's the flow of water into the filter, gravity takes over just like syphoning water from a hose.
Pump does not have to work all that hard after that.
If you fill the hose that draw's water from the tank (close the valve on end of hose) when priming the filter ,you see how gravity work's when the water rushes into the filter when you hook up the hose and open the valve.
Pump only need's to start the syphon .
Doesn't really have to pump too hard after that due to gravity.
The Siphon and gravity only account for 50% of the equation.
It was my understanding that the pump can't create the siphon which is why many of today's canisters will have manual pumps to get the initial siphon started.

The opposite end of that equation is returning the water back into the tank which is where the pump come back in.

What I don't know if its just the vertical high or the length of the hose will make the pump have to work harder or not.

Probably a PH.D in physics might know.

Thanks
 

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The Siphon and gravity only account for 50% of the equation.
It was my understanding that the pump can't create the siphon which is why many of today's canisters will have manual pumps to get the initial siphon started.

The opposite end of that equation is returning the water back into the tank which is where the pump come back in.

What I don't know if its just the vertical high or the length of the hose will make the pump have to work harder or not.

Probably a PH.D in physics might know.

Thanks
Length of the hose.
If you think the pump must have other than minimal capability to pump the water back into the tank, then run a garden hose or python hose from your tank, across say thirty five feet and up into kitchen sink such as I do once a week.
Suck on the end of the hose to start the syphon,and the water empties from my aquarium's with no other mechanical help until the water level in the tank becomes lower than the height of the kitchen sink.(about 50 % water change).
Now that spring is approaching I can open patio door and drain the water onto flower's.Too cold for this during winter.
I only use sink adapter on hoses to fill the tanks and sometimes use pump attached to hose to pump water faster from the tanks but pump is a bit large to hang on the glass inside the tank, and it smooshes plant's if I set it anywhere on the substrate.
Mostly use the pump and hose in pleco tank that get's more frequent water changes.
 

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Discussion Starter · #19 ·
From personal experience the question is not can it be done but should it be done.

The more direct path straight down to the filter, with the shortest hose possible, will create the greatest flow.

The less direct the path, the greater loss of flow.

What is acceptable is up to you.
Are you talking about flow loss from the incoming water or the outgoing water?

Which one are you advocating as the long hose? The intake or output?

Thanks.
 

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Are you talking about flow loss from the incoming water or the outgoing water?

Which one are you advocating as the long hose? The intake or output?

Thanks.
Keep in mind we might be talking about shades of gray. The optimum would always be the shortest most direct route to and from the filter. In practice, any actual loss may be minimal, albeit still some loss.

Sometimes it helps to extrapolate ideas to ridiculous extremes. Let's say one hose is 50' and other directly into the tank. If the input into the filter is the 50' section, it is being aided by the siphoning effect. If the output into the tank is 50', head pressure will limit the flow back to the tank.

At least that is the way I see it, and has been my experience. I would put the longer hose on the input side into the filter.

Again, in reality, if the filter is well sized for the tank, you might experience minimal differences, and it might be much ado about nothing. Much like micro toxicity, others may argue otherwise.
 
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