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FAQs about Canister, Cartridge Filters For Marine Systems, Plumbing 

Related Articles: Physical FiltrationReview of the ViaAqua Canister Filter

Related FAQs: Canister Filters 1, Canister Filters 2, Canister Filters 3, Outside Power Filters& FAQs on: Rationale/Use, Placement, Media, Maintenance, Troubleshooting/Repair, By Manufacturer: Eheim, Fluval, Other Brands,

Return Pipe/Plumbing 11/30/11
<Hello Rudy>
I have a canister filter and have a question on the best way to route the return line.
This is for a saltwater tank, from the return side of the canister filter I have 5/8� tubing going to a UV sterilizer.
From the UV sterilizer I can have a 5/8� tubing going up to the tank and connected to a return nozzle:
Or from the UV sterilizer I can have the 5/8� tubing connected to ¾� pvc pipe going to the top of the tank and connected to a return nozzle.
Distance from canister filter to tank top is about 3 vertical feet.
Which method will produce the least backpressure on the canister filter to maximize the water flow?
<Likely your last option but I wouldn't expect too much difference in flow over option two.
The most flow loss will occur in the UV unit.>
<You're welcome.  James (Salty Dog)>

Alteration to a canister filter for increased suction 5/27/2011
Hi Crew..
<Hiya - Darrel here>
Am back again'¦
<so you are. Welcome back>
Have a small query and sure to sound stupid too...
<Not all, SM. You'd have to work MUCH harder than that to come up with a stupid question - and trust us, we know -- we DO get stupid questions>
-- anyway feel better to take your advice rather than doing anything stupid'¦
<But wait '¦ how do you know our ADVICE isn't stupid???>
I have a 220 Gallon FOWL with a 35-40 Gallon sump. The sump is a 3 chamber set up with one having a DSB, one chamber hosing a Protein skimmer and the central chamber with the return pump. There are several pumps places on the side walls of the 6' ft display tank and cause much movements of the water through the tank.
While this takes care of the basic filtration, I still find fine particles of algae/debris/etc floating in the display tank. The movements in the tank keep it afloat and many such particles are not rushed through the overflow hole that flows to the sump.
<That's common. No matter how perfect our circulation is, the basic shape of the tank provides eddies and back currents and things get trapped>
I have a spare Eheim Canister filter (though much lesser in capacity for this tank) which I thought for using to suck in these floating matter. The problem is that the suction is too low and particles just float beside (if they do not happen to touch the intake pipe end) pipes and remain visible in the tank.
<Sounds like that Eheim sucks - because it doesn't suck?>
They are more irritating on days when I clean the tank (weekly once). Can I attach a power head (more powerful than the canister power head) to the suction tube to increase the suction rate? My purpose is just to suck the floating matter and not for water circulation?
Kindly advise
<OK - I will advise - and I'll do it kindly ï.>
<You can do what you're suggesting, you just have to make a few changes. First, you must remove the impeller assembly from inside the canister filter. If you have an internal impeller running, then the two pumps are fighting each other. If you leave the canister unplugged, then the impelling is an obstacle to high flow. So this is all conditional upon being able to remove the impeller what still keeping the water-tight integrity of the canister.>
<Which brings us to the second topic - structural and tubing integrity: The canister filter is designed to SUCK water from the intake tube, SUCK that water through the filter medium, SUCK it into the impeller which then FORCES the water out the output tube. The entire canister is designed for low to no pressure. If you were to take a power head like a Rio 32HF (1900 Gph) and force that much pressure into a small Eheim canister, you would either blow the tubes off of the fittings or possibly blow the seal out of the canister or maybe even blow the canister apart.>
<So yes, you CAN do what you're doing, you just need to be reasonable in the amount of pressure you put through the canister, put actual clamps on all your hose fittings and then test your assembly for 24 hours by just pumping water out of and into a bucket somewhere where leaking water won't hurt anything>
Re: Alteration to a canister filter for increased suction    5/28/11

Thanks Darrel,
<No charge!>
That was some well required input.
<Thanks! The law of large numbers states that I have to be useful & right at least once in a while. Hmmm '¦ should the next guy be worried?>
I thought on similar lines but clearly lacked the technical expertise.
<We learn from our mistakes & I know a LOT of things '¦ er '¦ wait '¦ that would indicate I screw up a lot, maybe I should rethink that '¦>
Feels that its not worth risking a very good canister filter.
<With a reasonable power head, I'd think you'd be just fine>
Anyway, this gives me an idea of a DIY top filter. Am planning to connect the power head to a small rectangular box and have a spray bar inside it. Intend to use rectangular filter pads( cut to size) place the spray bar right on top of these pads. This would drain directly into the Display tank again form a PVC drain outlet made in the box.. Less tubing, easy connectivity and no further problems in case of overflows/breakdowns.
Hope this works..
Thanks for saving my fave old filter
<Here is something even simpler: Get a high flow power head and just put a large sponge filter over the input. The flow will suck the small bits into the sponge and then, on cleaning day, you just place a net over the sponge, lift the entire unit out and then rinse it off. No tubes, boxes or leaks. Just another thought>
Have a good day
<You too!>
Srinivas Manian

Canister Filter intake inside Overflow Box 4/2/09
<Hello Jim.>
I spoke with someone at Glass-holes.com about getting an overflow box that would surface skim using a canister filter. They recommended that I write to you regarding this - he said ask for Scott V.
<Here with you.>
I'm currently running eheim pro3 on a 55 gallon cichlid tank. I wanted to know if a surface skimming box is able to be made to be used with canister filters.
<Well, this is a common question at G-H.com (I am part owner, have been gone for a bit of time here). Most ask how to put a closed loop intake in the overflow box.
It is the same basic principle, fueled by a short passage in a common reefkeeping book. Basically the main issue is air is brought in with the water and will be taken in by the closed loop or the canister. With freshwater this is much less of an issue. With a deep enough box (quite deep, with the filter intake near the bottom of the tank) you can do this, but you will not be collecting what is from the surface...
neither here not there in this case. You would be far better off just drilling for the canister intake and/or output if you want a cleaner look.>
Thank you for your help.
<Welcome, Scott V.>

Canister filter application 7/6/08 hello WWM crew, i <... the beginning of sentences, titles, the pronoun "I" H.N. are capitalized... Please heed our instructions if you want our help> have a question concerning the possibility of a modification to my Rena Filstar xP2 canister filter. My fish tank is 36"x18.5"x17" ~55 g. I have two 1 3/4 holes drilled in the back left side of my fish tank; one being 3"x3" away from the top left corner about to be used as a 3/4" inlet to a refugium I'm building, and another being 3"x3" away from the bottom left corner. <Good description... I wonder why the opening in the top left is so large diameter... and re the placement of the one in the lower left> What i would like to know is if i can attach my inlet tube from the canister filter to the bottom hole and let it drain through a 1" inlet into the filter. <Mmmm> I'm worried about possibly overworking the filter since i believe the pressure would force more water to run through the filter normally. <No... not if all is sealed, the discharge is about where you propose... the overall pressure in the unit will/would be about the same> Here are the specs of the filter: flow rate=300 U.S. gph, aquarium vol.=up to 75 g, canister vol. 1.4g, power=16w, amps=0.368, max. water head 55 in.(1.40m), and water flow of 160 g (with media and accessories). No other accessories except the foam, micro-pads, and activated carbon. The filter will sit 4ft. below the hole. If i set this up correctly, would the filter be degraded in any way? <No, but...> Just as well, are there any problems with this set up if i used a 2" in. sandbed? <See WWM re: http://wetwebmedia.com/marine/setup/index.htm Scroll down to "Marine Substrates"...> And would there be any flooding i have to worry about if the power shuts off?? <Not this, but...> Thank-you for your time, H.N. <Am very concerned, VERY re issues of the placement of the bottom left cut-out... what if the canister somehow has "troubles"... the water will (quickly) drain down to this level... where will the water be? And when you want to work on the unit... do have valving installed... If it were mine, I'd run the canister plumbing lines over the top of the tank... use the present through-puts perhaps for closed-loop circulation. Bob Fenner>

Plumbing 4/10/07 Hi guys, <Hello Tim> I have a 120-gallon All Glass aquarium w/dual mega flows. This was initially set up to feed a homemade wet dry w/ a 75-gallon sump. All was well until I had to move from a house into a Manhattan apt. Without the additional space of a house I do not have the room the wet dry requires. So I am forced to switch to a smaller solution. I went out and purchased an Eheim Professional 3 canister filter that I had planned on hooking up to one of the mega's. Upon opening the box I quickly realized that the two were not a match made in heaven. Do you have any suggestions on how to reduce the large bulkhead into the small Eheim intake? I have just returned from the local Home Depot and the didn't seem to have a reducer suitable for the task. <I'd try here, should be able to conjure something up.   http://www.usplastic.com/catalog/category.asp?catalog%5Fname=USPlastic&category%5Fname=13670&utm_source=google&gclid=CKy66-SXuIsCFRKPgQodGmj8yQ&cookie%5Ftest=1> Thanks, <You're welcome.  James (Salty Dog)> Tim

Multiple Canisters on a Reef Tank.  9/28/05 <Hi, Adam J with you.> I have a 44 Gal Pentagon Salt Water reef tank and I am currently running a Fluval 204 canister and I want to add a Fluval 404 canister to the filtration of the tank.  Is it possible to daisy chain the 2 filter in line together? <I would run them independent due to the different flow rates and incase one of them fails to operate. In my opinion 'combining' them would only add more complication.> I would prefer to use the 204 as the mechanical and chemical and the 404 as the mechanical and biological.  Or would it be better just to run the 2 independent of each other? < I would much rather add a larger/more efficient skimmer than your current prism to the system rather than another canister filter which have been known to be, dare I say, nitrate factories. Looking into refugiums would not be a bad idea either.> The inhabitants of the tank are as follows: about 30 lbs. live rock with some hitch hikers crushed coral bed Giant Blue Carpet Anemone <This anemone will eventually outgrow your tank, and possibly eat some of your inhabitants.> Torch Coral Blue Crocea Clam 2 Peppermint shrimp 30 Astrea Snails 30 Blue leg hermits <Far to many snails and hermits for this size set-up, make sure they are all getting adequate food.> 2 Green chromis 2 Yellow Tail damsels 1 Blue Devil 1 Yellow Tang <This fish will very quickly outgrow your current tank.> 1 Black Perc  (I think it's a Black Saddle back) Fluval 204 Filter Prism Protein Skimmer 2 Maxi Jet Power heads 230 Wt Lighting on for 12 hours (150wt MH,  80wt PC) Thanks !! , Joe Piazza <Anytime, Adam J.>

Equipment/Pumps/Plumbing    5/2/06 Hello Crew, <Hello John> I've Google'd this topic and haven't found any hints or answers, so it is time I ask you...I'm setting up a 90g AGA with the Megaflow overflow kit.  I have an Eheim 1262 for the return from my sump/refugium.  My problem is plumbing the Eheim, with metric connections, to the 3/4" Megaflow bulkhead. If I use Eheim/metric tubing, it won't fit on the bulkhead, but if I use 3/4" tubing it won't connect to the Eheim.  Any hints or ideas? BTW, the Eheim is rated for higher flow than the Megaflow, but I plan to bleed off some of the return via a T into the refugium. <You might want to dip the tubing in boiling water to soften it, then try to slip it onto the barbed fitting.  I have done that a few times with good results.> Thank You  <You're welcome.  James (Salty Dog)> John H.

Which Option For Plumbing A Separate External In-Line Filter? - 01/18/07 I have a 142 gallon aquarium that drains through a 12" x 12" central overflow via a 2" Durso standpipe into a 30 gallon sump. <<Ok>> A Reeflo Barracuda then pumps the water back into the tank at about 1500 GPH.  I want to run a second loop through a Nu-clear 533 filter, primarily for additional circulation and chemical filtering with Purigen and PhosGuard. <<I see...excellent>> I have a Little Giant 4MDQ-SC for this purpose, although I would like to eventually replace it with something cooler and quieter. <<One of the small Iwaki or GRI pumps would do nicely...even BlueLine or PanWorld for a bit less dosh.  Choose the smaller models without the cooling fan for less noise...would still be plenty of flow for the purpose of the filter>> My question is, how should I supply this second pump? <<Preferably with its own throughput/bulkhead fitting from the tank>> I have three available options.  The first is to feed it through a 1" bulkhead in the bottom of the overflow. <<Mmm...only if the overflow can take the extra volume...I believe RC has a 'calculator' for this>> The second is to use the currently plugged hole in the side of the overflow near the bottom, and then through the 1" bulkhead in the bottom of the overflow via 1" tubing.  In that way, it will draw water from the tank outside of the overflow, not from within the overflow itself where it may compete with the 2" drain. <<Indeed...this is a much better option in my opinion.  The bulkhead in the side of the overflow can easily be fitted with a screen to protect livestock>>>> The final option is to feed the pump from the sump, but will that be too much for the sump or drain to handle? <<You'll be pushing, maybe even exceeding the limits of the drain...at the least this will create more noise/turbulence, and the associated plumbing hassles to resolve same>> Thank you very much for any assistance that you can provide! <<Best to go with option two in my opinion.  This is the approach with the least hassle and the best chance for success...you will in effect be creating a closed-loop with an in-line filter.  Regards, EricR>>

Using A Manifold With An Eheim Canister Filter 1/10/07 Hi crew! <Hello Laura.> I read through the info on the Goodbye Powerheads article and was wondering if this manifold idea would work if I built it and ran it out from the return on my Eheim 2028 canister filter (rather than having to add another pump to my already crowded 55 gal. reef tank).  What do you think? <Laura, the Eheim pump that is incorporated into the filter will more than likely not develop enough pressure to use a manifold with it.  The Eheims usually come with a spray bar option, and this is what I would use.> And also, does this manifold really allow a tank to flourish without the use of all these powerheads? <It does help to eliminate dead spots in the system, and yes, can take the place of several powerheads if the pump is sized correctly.  Do search our site on this subject for more info.> I will admit I am a bit skeptical, but I'd love to give it a try if I can eliminate them! Thanks so much for this wonderful site and your expert advice! <You're welcome, and thank you for writing us.  James (Salty Dog)> Laura

Plumbing in a Large Canister Filter Hi Bob, <Steven Pro this morning.> I am about to embark on my first PVC project, and I'm stressing. <No need to.> I'm trying to connect an Ocean Clear canister and Mag-Drive 12 to my tank. If you can you recommend any websites or articles, or give any suggestions I would greatly appreciate them. My biggest concerns are "gluing myself in a corner" so to speak. That is, I'm not sure where in the line I should put any valves and/or unions. <Before and after anything that may need cleaning or replacement.> I don't know what types of elbows to use where. <Schedule 40 PVC is best, if that is what you are talking about.> Do they make PVC adapters that are threaded on one side and have a PVC slip on the other? <Sure> Also, how can I prime the pump once it is "hard wired"? I attached a diagram of my proposed setup. <I have never used an Ocean Clear canister before, but you should be able to open the unit up to replace/clean the micron cartridge. You should be able to simply open it up and pour some water into it to prime the pump.> Thanks for all your help, Adam <I looked at your drawing. It appears fine. I would place true unions right before the canister, between the canister and pump, and after the pump. -Steven Pro>

Re: Canister filter (water flow) Hello, I have a 54 gal. corner tank which I bought with an under gravel filter.  I just bought and installed a Fluval 304 canister filter as well.  My question is regarding the current the new filter creates.  How much is O.K.?  I have the filter valve partially closed to slow it down a little for now.  When the valve is open all the way the current is pretty strong in my tank.  Any advise would be appreciated. Thanks, Kurt Will   <Please see here: http://www.wetwebmedia.com/circmarart.htm the same principles apply to freshwater circulation considerations. Bob Fenner>

Re: Flow question in a seahorse tank (03/11/03) Thanks for the info Ananda; <No problem> I like your idea about the Fluval.  I checked some of them out.  If I got rid of the power filter and went with the Fluval would my tank get enough oxygen.   <Sure. It's just a matter of directing the water flow.> The do have a spray bar that you can get to attach to the Fluval <You could also make one of tubing (bring the powerhead part of the filter to the Home Depot/Lowe's/etc and pick the tubing that fits), with suction cups to hold the tubing where you want it....> and I could run it along the back of the tank, maybe like, across the top quarter of the back wall.  I know as long as you get a good ripple across the surface of the water, you will be getting enough oxygen in the tank. Does that sound right to you???? <Yup.> Thanks again; Kevin <You're welcome. --Ananda>

Inline UV Question Can I run an Eheim 2213 canister filter inline with my Aquanetics 8watt UV sterilizer?  This is for a 37 gallon fish only marine tank. <You can but it will affect flow rate some.  Craig>

Plumbing Dilemma... I just acquired a 70 gallon reef ready tank . its got 3 holes on the bottom of the tank  and 2 on one of the ends about 2/3 to 3/4 the way up. I have two canister filters and I'm not sure how to plumb this set up. As of right now I'm not sure if I'm going fresh or salt but I've got to get this plumbing thing figured out. <The fun part...LOL> Should the return lines be on the bottom of the tank with check valves in case power out age? <Frankly, check valves scare the hell out of me! They are vulnerable to failure...at the most unfortunate times... I'd prefer something above the water line, like Sea Swirls, which have the added benefit of oscillating water flow...Neat stuff...> And the line feeding into the pumps be the ones on the side? I just can't find any info out for this kind of tank. <Well, there are about as many approaches to tank plumbing as there are hobbyists...No real right or wrong answers...Just do what works or you, and remains reliable and functional...> I'd really appreciate your help  , and maybe I'm way off , any suggestions ? <As above...check out Sea Swirls for returns...> I'm lost. Thanks. Sean McConnell <Well, Sean-there are lots of approaches here...you can look into plumbing on the WWM site...lots of good information here- check it out! Good luck! Regards, Scott F.>

Oxygen content Hi, I checked the search tool for my question with no luck. So forgive me if this was already asked. My question is about octopi. I'm setting up a 30 gallon cube tank with a canister filter. I have heard that octopi need higher levels of dissolved oxygen content, but I'm not exactly sure what that means. How should I keep it high? Or is what I have good enough? Thanks a lot and again sorry if this was already asked.  <Ben, the canister filter is not going to give you the oxygen level you need. You really need a wet/dry filter for good air/water exchange. James (Salty Dog)> 

Oxygen content Follow-up  Hey  <Hey here> Thanks for your quick response. My LFS told me this would be enough so I spent 200 dollars on it. Is there anything else I can do?  <What will help some is to have the return water break the surface of the tank water. That is, do not submerge the return line, preferably use a spray bar. Some filters come with this. If he sold you a Rena or Eheim, it will include the spray bar. James (Salty Dog)> Thanks Ben <You're welcome>

100 gallon tank, mainly filtration... Tank goal: To keep corals, mushrooms, Caulerpa, and slightly delicate fish like angels, etc. Yes Bob, I have a little more than 500 pc watts to keep those corals and algae growing. <Okay> I have bought a 100 gallon tank which has been sitting around for several weeks but I just can't decide on what type of filtration to use. I thought I had it all figured out but every fish store I go to disagrees with my idea.  <As long as you agree with yourself... that's all that matters> I am planning to use an Eheim 2060 (500gph) with a large skimmer and plenty of live rock (60-80 lbs). If I ever find a simple, easy to understand sump system I may at sometime in the future add a sump but that probably will not happen immediately unless you think it is a necessity.  <Good attitude... or at least we're in agreement> Four sales people at different shops and even Petwarehouse have all said "Get a wet dry" but I don't want the added problems that are cataloged on your website. <A sump is a sump... you don't need a wet-dry... I wonder how much money these folks might make by selling such off the shelf systems...?> These sales people insist that the Eheim won't be enough filtration because: 1) it won't turn the tank over as many times as I will need for a quasi-reef/fish tank, <The live rock is/will be the primary filter...> 2) gph on canisters decrease every day the canister is used so the gph is constantly decreasing,  <Not so much with a properly packed Eheim... I speak from decades of using them> 3) one canister will only take the water from one end of the tank therefore not cycling as much overall water is needed, and other similar complaints.  <Uh, the tank only has two ends... and you can/should use submersible pumps, powerheads for more circulation, aeration...> I want a simple, low maintenance filtration system that is effective (performance and cost) as well as operating quietly and that will be difficult for me to misuse.  <Your insight astounds me!> Eheim with live rock and a good skimmer sounds like a winner to me but no one else seems to agree. <Umm, I do.> I have read lots of info and at this point and have resigned myself to taking whatever your suggestions) is. <My advice is, of course to only let only your conscience be your guide... You're on the/a correct path my friend. Bob Fenner> Thanks once again, David Dowless

Film on surface Hello, <Hey there> I have cycled my 80 gal tank for three months now and achieved no ammonia or nitrites, etc. <None perhaps detected... they were expediently converted, absorbed...> I added 6 Damsels last week and thus began feeding. I now notice a layer of what appears to be oil/film on the surface of the water. <Ah, good observation!> It also contains some debris, maybe from the fish/food... I have a Tunze protein skimmer and an Eheim canister filter. Is my skimmer working properly? <Likely yes. A very good unit, manufacturer.> Or do I need to get an Eheim surface skimmer? <Ah! Excellent choice.> What is this film & why are the debris not being sucked up by the equipment? <Products, by-products of chemical/physical activity in your (and all) system, and resultant from feedings, etc.... No real problem if kept to a minimum... with "scooping" water from the top (like with a pitcher), or skimming with a clean, unscented paper towel... or best with the proposed Eheim addition> I have been feeding some jarred zooplankton, could that be causing trouble? <To some degree, yes... likely a source of the oil you're so keenly espying. Be chatting. Bob Fenner>

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