# ZooMed 501 vs Finnex PX-360 for under the tank's



## bastage (Dec 21, 2011)

So I have a 55g stand that has a Flora, a standard 10g & a Ebi all on it in a row. Currently I have an internal filter on the flora, a hob on the 10g & a ZooMed 501 on the ebi. Well this is in my bedroom & my wife wants it quiet so the HOB has to go. Well I want them pretty so the ugly arse internal filter in the flora also needs to go. 

Currently the zoomed is behind the 10g with the pipes ran back behind the ebi. Well this wont work if I add another 2 canisters as there will just flat out not be enough room so the canisters are going to have to go under in the stand. Plus this just looks better to not have to see them. 

So I have read that both of these filters wont work under the tank because they use gravity, well as someone who understands basic physics that's BS since the water pressure will always try to equalize & I know that the only real difference is in the resistance of the water flowing through the pipes. which should be limited. 

So that said what is everyone's opinion of these 2 filters keeping in mind there will be several feet of tubing on each. 

Also of note. I already have an aquatop and have nothing against aquatop/sunsun, but they don't make one small enough for me to get 3 of them in the stand easily since it only opens up in the middle. So please don't say I should get a sunsun as its not going to happen.


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## OVT (Nov 29, 2011)

I have no experience with ZooMed 501 but I do have 3 Finnex PX-360 in operation. There are a number of posts, including mine, on this forum on the subject.

The short story, Finnex's claims aside, PX-360 has a practical head of about 6". I could not get any reliable flow with anything higher then that.

As far as the physics goes, if the flow was one-directional (down) all filters would have infinite head. The problem is that gravity is a vector. Therefore, something, i.e. motor, has to push water up against the gravity, tube resistance, water and atmospheric pressure.


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## bastage (Dec 21, 2011)

OVT said:


> I have no experience with ZooMed 501 but I do have 3 Finnex PX-360 in operation. There are a number of posts, including mine, on this forum on the subject.
> 
> The short story, Finnex's claims aside, PX-360 has a practical head of about 6". I could not get any reliable flow with anything higher then that.
> 
> As far as the physics goes, if the flow was one-directional (down) all filters would have infinite head. The problem is that gravity is a vector. Therefore, something, i.e. motor, has to push water up against the gravity, tube resistance, water and atmospheric pressure.


The filter does not push against gravity. If the intake was low & just the output high then yes, but with both being sealed until it hits the aquarium which gives both sides the same water level. Your Atmospheric pressure also makes me lol since the only exposed atmosphere is the tank surface which its not pushing against since you are not raising the tank water level. The resistance of the tube is the only effect. Of which a change in materials from the standard rubber/nylon tubing can reduce.


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## samamorgan (Dec 31, 2011)

bastage said:


> The filter does not push against gravity. If the intake was low & just the output high then yes, but with both being sealed until it hits the aquarium which gives both sides the same water level. Your Atmospheric pressure also makes me lol since the only exposed atmosphere is the tank surface which its not pushing against since you are not raising the tank water level. The resistance of the tube is the only effect. Of which a change in materials from the standard rubber/nylon tubing can reduce.


Everything you just said is completely wrong. That is all.


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## bastage (Dec 21, 2011)

samamorgan said:


> Everything you just said is completely wrong. That is all.


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## samamorgan (Dec 31, 2011)

According to your _*flawless*_ logic you could put a filter 100 feet below the top of the aquarium and it would still pump just fine, because its just one big pool of water in a closed system! I'm so glad you enlightened me, I always thought the manufacturers were wrong when they talked about that head height thing.

http://www.aquarium-pond-answers.com/2011/09/head-pressure-in-aquarium-and-pond.html


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## bastage (Dec 21, 2011)

samamorgan said:


> According to your _*flawless*_ logic you could put a filter 100 feet below the top of the aquarium and it would still pump just fine, because its just one big pool of water in a closed system! I'm so glad you enlightened me, I always thought the manufacturers were wrong when they talked about that head height thing.
> 
> http://www.aquarium-pond-answers.com/2011/09/head-pressure-in-aquarium-and-pond.html


Great lets talk about head pressure.. 



> Head pressure is the difference between the water level you are pumping from and the water level you are pumping to. If you are pumping out of your tank and back into it, the head pressure is 0.


(that was stolen from another thread here) 

Another user in the same thread also worded it well.. 



> There is exactly as much water weight pushing down the back side as the motor has to push up. The only difference would be the additional friction caused by the extra length. Some of this could be offset by moving up to the next size hoses.


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## OVT (Nov 29, 2011)

At least the OP got my personal experience with Finnex PX-360. And you are welcome.
How that will be used is none of my business.

I will be swapping all of my Eheim 2075s for Finnex 360s with 3/4" tubes. Won't even have to plug the filters in - the pumps are useless anyways.

The last "scientist" that tried to defy the law of gravity left a nice wet spot on the ground. The supporting quotes give me hope for more wet spots in the near future.

We can LOL together once we are at the same level:

http://en.wikipedia.org/wiki/Hydraulic_head
http://www.engineeringtoolbox.com/pump-head-pressure-d_663.html


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## astrosag (Sep 3, 2010)

No head pressure, just friction. Sorry guys. Helping balance gravity is the pressure of the water column from the intake. Nice try though


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## OVT (Nov 29, 2011)

astrosag said:


> No head pressure, just friction. Sorry guys. Helping balance gravity is the pressure of the water column from the intake. Nice try though


Indeed, with 0 flow, which is very useful.
If you can generate 1 gph flow at 1" head without external energy you would have the first ever working Perpetuum mobile. Nobel Prize is on it's way.


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## Craigthor (Sep 9, 2007)

Eheim 2211's would be perfect for smaller tanks and placing the filters under the tanks.


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## astrosag (Sep 3, 2010)

OVT said:


> Indeed, with 0 flow, which is very useful.
> If you can generate 1 gph flow at 1" head without external energy you would have the first ever working Perpetuum mobile. Nobel Prize is on it's way.


Your sarcasm is cute. No, sorry not a girl - I know people don't say that to you often...but

In a closed system with 0 flow, you'll have 0 pressure at the top and the water column's weight (hydrostatic pressure) at the bottom - for incompressible fluid. Sure, one side is fighting gravity, but again, the other side is assisted by gravity. The primary thing a pump is fighting is friction which varies on pipe length. 

You must be a political science major :hihi:

P.S. To be a bit more clear, what I'm saying is head loss due to friction. I should have been clear but someone versed in physics would have understood when I said no head pressure in a closed system - just friction.


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## astrosag (Sep 3, 2010)

samamorgan said:


> According to your _*flawless*_ logic you could put a filter 100 feet below the top of the aquarium and it would still pump just fine, because its just one big pool of water in a closed system! I'm so glad you enlightened me, I always thought the manufacturers were wrong when they talked about that head height thing.
> 
> http://www.aquarium-pond-answers.com/2011/09/head-pressure-in-aquarium-and-pond.html


Actually your example is a fallacy.

You're not accounting for the incredible friction loss from 100 feet of tubing. Now* your* logic is a bit less flawed!


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## DerekFF (May 24, 2011)

Now that im thinking about it (no physics degree but i am Japanese so that gives me +10 math and science points yeah!??) 
The physics behind a CLOSED system like a canister filter should only be effected by friction loss through the tubing and a super minimal head pressure loss where the water needs to be pumped over the lip of the tank and therefore above the water line. Sorry peeps but the laws of physics dont lie, and the key word or point here is that it is a CLOSED system aka canister filter 

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## astrosag (Sep 3, 2010)

^
Yes.


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## bastage (Dec 21, 2011)

Thank you astrosag & DerekFF 

Back more to the lines of the actual topic rather then basic physics. 

the stand is only open for about 18" in the center & being only about 1' deep I have minimal space to work with without wrapping the tubing around & greatly increasing the friction of the tubes (see what I did there). So that is why I am needing to stick to the smaller filters. Plus the smaller diameter tubing would also help. as far as keeping everything serviceable in the relatively small area. 

I Know that some full size canister filters are pretty small (like the eheim classics), but then it becomes simply a cost factor. I can get the ZooMed 501's for 32 bucks each with no tax or shipping cost from amazon right now where as the cheapest Eheim classic is 77 on amazon. So thats about 2 1/3rd the cost. Also of note as there are betta's in 2 of these tanks having too much flow is much more likely then too little with any canister filter. 

And if it wasnt for the space issue & the larger diameter tubing I would just order a couple more aquatops as the one I have now has been very impressive for the short time I have had it & the flow rate can be easily turned down for my betta's.


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## astrosag (Sep 3, 2010)

Several feet is quite a lot for a 501. I have one and even keeping it at tank level, I can easily baffle the flow with a weak sponge. If that's any indication then several feet of tubing (each way) is going to severely lower your flow rate. On the other hand, if the tank is well planted and isn't overly stocked, then you actually don't need much flow.


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## bastage (Dec 21, 2011)

astrosag said:


> Several feet is quite a lot for a 501. I have one and even keeping it at tank level, I can easily baffle the flow with a weak sponge. If that's any indication then several feet of tubing (each way) is going to severely lower your flow rate. On the other hand, if the tank is well planted and isn't overly stocked, then you actually don't need much flow.


I plan to do some research & find some tubing with a lower then standard internal friction to compensate for that. The tanks are not heavily planted, but they do all have very low bio loads.


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## DerekFF (May 24, 2011)

Well the larger the hose the less friction loss. And i think the regular old plastic tubing is about as smooth as any will come. You can always put a ball valve inline to adjust waterflow

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## OVT (Nov 29, 2011)

*Mea culpa*

I do stand corrected, eating my own words. My apologies to all concerned.

In a *closed* system, which a canister filter is, arguably, an example of, all external energy is indeed used to replenish energy wasted to overcome friction, mostly due to turbulent flow through the filter media.

:redface:


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## astrosag (Sep 3, 2010)

All good bro. My apologies for being a bit harsh - I just didn't appreciate the sarcasm shot at the OP and then me lol. 

It's all a learning process and I should have refrained from personal attacks - never reflects good on anyone.


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## OVT (Nov 29, 2011)

I did go overboard. Live and learn. Cheers.


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## bastage (Dec 21, 2011)

DerekFF said:


> Well the larger the hose the less friction loss. And i think the regular old plastic tubing is about as smooth as any will come. You can always put a ball valve inline to adjust waterflow
> 
> Sent from my DROIDX using Tapatalk


Regular plastic tubing is actually very not smooth inside. If nothing else though I will use some semi rigid plastic pipe & I can "polish" the inside using a drill & a pipe snake as well as some sort of buffer at the end. Nothing extreme, but should make some difference. I Also do plan to oversize it a little, but not much as it would then defeat the purpose.


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## DerekFF (May 24, 2011)

bastage said:


> Regular plastic tubing is actually very not smooth inside. If nothing else though I will use some semi rigid plastic pipe & I can "polish" the inside using a drill & a pipe snake as well as some sort of buffer at the end. Nothing extreme, but should make some difference. I Also do plan to oversize it a little, but not much as it would then defeat the purpose.


Interesting idea

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## OrangeSoda (Jan 15, 2011)

Also factor in that the 501 and 360 were engineered for the short hoses they are packaged with. The further below the tank the canister is, the higher the pressure is. The motor may be able to push the water, but will the canister itself be able to hold the pressure without blowing a seal? I've never owned one so I'm not sure how they are sealed. If you do this watch for leaks and good luck. I'll be interested to hear how it goes.


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## DerekFF (May 24, 2011)

^^ also another good point lol

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## bastage (Dec 21, 2011)

OrangeSoda said:


> Also factor in that the 501 and 360 were engineered for the short hoses they are packaged with. The further below the tank the canister is, the higher the pressure is. The motor may be able to push the water, but will the canister itself be able to hold the pressure without blowing a seal? I've never owned one so I'm not sure how they are sealed. If you do this watch for leaks and good luck. I'll be interested to hear how it goes.


If I was going 20 or 30 feet below I would be worried about this. But the 4 3 feet of difference I am not at all concerned about as far as the water pressure goes.


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## mistergreen (Dec 9, 2006)

I have my finnex under my tank. It runs fine. The hose isn't long enough to reach the floor. It's 3" under the tank.

It's not super quite but more quiet than a HOB.


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## bastage (Dec 21, 2011)

mistergreen said:


> I have my finnex under my tank. It runs fine. The hose isn't long enough to reach the floor. It's 3" under the tank.
> 
> It's not super quite but more quiet than a HOB.


Thanks for the feedback. Did it get louder when moved to below tank level?


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