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Dual canister filters?

11K views 30 replies 16 participants last post by  alcimedes 
#1 ·
ok so im currently running a single 264gph sunsun canister filter on my 75 but i feel its not enough so i was wondering if a dual set up like in the (clearly Van Gogh level) illustration above would be possible if i purchased another 264gph filter of the same model and ran the outflow from one to the intake of the other and made the first a purely mechanical filter and stuff it to the brim with levels of filter floss and then the second with nothing but bio media and then ran the latter's outflow back into the tank. I have had this idea for a long time now but just never got around to actually looking into it till now and i would greatly appreciate any help

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#3 ·
#6 ·
#5 ·
That's an interesting idea. I have 2 Marineland 350 Mag filters that I use, but I currently have both setup on their own intakes and outflows. I had an idea of combining the outflows into one spraybar (see below), but I never thought about daisy chaining them together. Please post back if you do attempt this, and let us know how it works.
Only problems I could see is the first filter (mech) slowing the flow too much for the bio filter, since the bio filter would in theory have less resistance, and might push water out faster than it comes in.

 
#8 ·
I personally like the second idea better. Less to go wrong. For example in the first idea if either filter quite pumping you would have an issue. With the second drawing it would only mean reduced flow. The second plan would also allow you to keep running while you tear one of the filters down for maintenance, assuming you build the plumbing correctly.
 
#9 ·
I would go for batting Large quantities of dirty floss is a yucky mission to deal with when you are done with it.

What I have been eyeing is one of these mini (sand) pool filters that comes with larger portable swimming pools.
Although the target is for a pond.
 
#12 ·
@ShadeSlayer please keep us informed if you do this. I will subscribe as I am interested in how this works out for you. I want to add something else. If I was doing this I would consider using extra shutoff valves and place them strategically where you can see you might have to take apart the plumbing for cleaning and maintenance.
 
#14 ·
Only problem I've had was planning the actual plumbing with my idea. I was trying to use mostly hoses to keep from using 90* bends and reducing flow with barb -> pvc fittings. If someone has some ideas I'm more then open to trying to come up with a working model.
 
#15 ·
Go to a slightly larger size vinyl tubing and increase the size of the pvc accordingly. The main issue I see with design A is if one of the canisters dies the other will work twice as hard to move the water. If the first canister clogs and slows the second will starve for water to pump.

I think if it was me, unless this is an experiment that you want to do for the sake of trying it, I would add a powerhead and sponge. It is cheap, effective means of adding both bio and mechanical filtration, simple to maintain, will increase tank flow and is easily directional. Oh and did I mention cheap?
 
#16 ·
I'm a firm believer of the KISS method. Keep It Simple Stupid.

I would just run both filters independently, like how they were designed to run. This way, any issues with flow, operation, etc, can be dealt with, without the complications. My $02.

I think some good questions would be, what are the advantages? What modifications would you need to make? What kind of additional hoses, tubing, pipes, etc would it add?
 
#17 ·
I tend to agree with you which is why I recommended the sponge and powerhead. I have to admit I also like these kinds of projects. You learn a lot trying to maximize what you get out of your equipment and if we only used what we know works then there would be no bdbs substrate/caps, no safe t sorb substrates. Lots of cool and interesting ideas and things come about by pushing the envelope.
 
#18 ·
Unless you are trying to really limit flow into the tank (which in the course of this setup may damage internal pumps) there is no benefit for this. Most tanks do better with more flow... the kind you would get with two or more filter outputs. If anything do one filter with nothing but bio media and the other with actual filter floss and filter media. Remember the water flow will stop at the first restriction so packing all that into one output is going to double or triple the frequency that you would need to clean the filters to keep any appreciable flow
 
#19 ·
You're on the low side of flow for a 75g if the sunsun was pumping advertised flow, which it is now. I would add at least another 302, if not a 304 to the tank. Do not splice the returns together. It is not advantageous and definitely do not run them in series. Water flow is not like voltage. :D If you want the spray bars set up like you have in the second drawing, just run both of the returns over the back in the center and branch away from each other that way.

I had a 75g with a 304 in it for awhile. I also had some air stones and was flowing quite a bit of water with the air movement. A single 304 really isn't enough flow or surface agitation and a 302 is definitely not enough, in my opinion. Remember, this is all opinions.
 
#20 ·
I have a powerhead running that i believe is an 80 gph i use it to help my co2 atomizer to diffuse the co2 more efficiently also i have a veil tail betta in the tank. But i think i may just go with a second one run separately and I'll at least try my design for science sake lol

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#23 ·
Split the bio media in the 2 filters, alternate cleaning those filters. I run twin eheims on both my 90g and the 65g. That way at cleaning intervals you can do a real thorough cleaning and not stress too much about the bio media. I also run an intake on either side of the tanks which will remove stuff from the tank more efficiently. One intake does half the job of 2 IMO. Myself I don't really see the point on this one.

Best of luck, keep us posted on how it turns out.

.
 
#25 ·
I think a couple people were confusing myself and the OP.

My filter are running independently right now. Both with mech and bio filters. I was looking to combine the outputs, more for aesthetics and simplicity, and to more evenly distribute flow. Currently I am running them as pictured below. With a DIY spraybar on "Can 1" and the stock nozzle on "Can 2" pointing towards the middle of the tank. I get a bit of a dead spot right under the intake for "Can 2" where all the fish crap settles on the bottom. I would love to move to a single canister with the input and output on opposite ends, with perhaps a powerhead added in, but there are very few affordable options for a 75 gallon.

 
#26 ·
I am running two canister filters on one tank right now. I wanted more flow and had an extra sitting around. I simply just put a T in on each side, one between the inflow of both canisters and one after the outflow. Many will say it makes more sense to run two filters separately, and I would agree, but my tank is on the smaller side so the extra inflow/outflow would be pretty evident, plus I didn't have a lot of space to plumb this outside of the tank so I just decided to go for it.

So far I haven't experienced anything that leads me to believe this is a bad idea. Many say running them in parallel, meaning the outflow of one goes straight into the other can damage the pump which I don't know to be true or not. Many others say it just doesn't up the flow much, basically the first canister is still a restriction on the first, or the second, now being pressurized, can't keep up. I don't know if this is true either, I imagine it all has some merit but I don't know in practice.

The only downside I have identified is that with only one outflow, you cannot easily improve dead spots. Sure, you get more flow but it still is from one place. Because I am using lily pipes, rather than a spray bar, I imagine this is more of a problem with the type of outflow I have. The inflow can also clog more quickly/easily when I have melting or die off/high organic matter but not enough to stop or slow flow enough to worry.

My long term concern is how easy this will be to clean. I don't clean my canisters often so I have yet to try. Two major issues that may arise. One is, between the tubing and stand size, there is not much room to work. It may be simply challenging to pull them out routinely. Second is priming them. One of my canisters primes easily, the other does not. The first time I set it up, I primed the one that has a priming function which filled the other decently, then I found that when I turned that one off, the opposite filter did remove the existing air, well most of it. I don't believe Sun Sun's are easy to prime, the only reason I bring that up. Having one canister that has a priming function makes this work OK, I don't know I would get this working without that, if I lost gravity feed.
 
#27 ·
The problem with running two filters series fashion is that when one is stopping up they will both lose flow. I would not consider it but look more to using two filters as stand alone and any extra work/thought would go to hiding the extra in/out. With two, neither will require work nearly as often. One stuffed full will require lots of attention. Good mechanical media before the bio-media keeps it clean for a long time. When it does get gunked up, a simple rinse will renew it.
 
#28 ·
In my opinion, if your plumbing two canisters to the same tank, it is best to plumb them as two separate filters and not try to connect them in series, like in the op's post or connect them together as in a later post.

What happens is that no matter what you do, one pump will run a little faster than the other one, and they will fight against each other in moving water.

I feel the best way to use two canisters is to put the intake from on on the left side and put the return on the right side. Do the exact opposite with the other filter. This way you get better circulation.

If you want to fill one filter with bio media and the other with mechanical media, that's fine too.
 
#29 · (Edited)
The problem I can see with two pumps in series is pumps are meant to run at maximum peak continuously. If you tie them together, one pump will probably overwork the other. Canisters can leak if you overpressure them. You can see it when you turn them on and off. The head lifts up and down. Same might happen if one pump overworks the other. You might even run the risk of cavitation.

It would be better to plumb them higher up and tee it off so the pumps can draw their own without being forced/denied.

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#31 ·
Hmm. I'd just run one canister filter with purely mechanical filtration and a large pore sponge on the intake.

Then for the other canister filter, put a fine port sponge on the intake, and that's your bio filter.

You'll have to open and remove muck from the mechanical one with some regularity depending on stocking levels and feeding, but for the bio filter you should just need to remove the sponge on the intake and rinse it, then put it back. The bio filter shouldn't really clog that way, and you'll likely only have to clean it once or twice a year.

It also avoids the issues of trying to have pumps in a series.
 
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