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FAQs about Canister, Cartridge Filters For Marine Systems, Troubleshooting/Repair

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

Mmm, best to prime these units by starting with suction on the discharge side, allowing water to siphon in through the intake/s... filling the unit/s... perhaps tilting, inverting to clear last bubbles.

Reviving biological filter in Eheim Canister 1/8/12
Hello and happy new year!
<A week later?! My liver is still out of commission!>
I went to do a water change in my 65 gallon saltwater reef tank, and realized my Eheim Canister had lost power at some point since my last change, 2 weeks ago (the spray-bar is submerged, so I hadn't noticed). It is filled with a mixture of Substrat Pro and crumbles of live rock, as well as about a 1/2 cup of carbon (in a bag) and filter floss on the intake.
When I drained it, it smelled, ummmm, gross. Like dead stuff and maybe a little sulfur-like. Gross. So I rinsed it and flushed the canister/tubing with the old salt-water I took out of the tank, then fresh RODI water.
<Good move>
It still doesn't smell awesome. Much better, but not awesome. So I'm wondering how to proceed from here? I have an empty 10 gallon QT that I could set up with fresh salt water to let the media cycle, or is that overkill?
<Use some of the established system water... And no, not overkill.
Cautious, and reasonably so>
Would a few more flushes with RODI be sufficient?
<Mmm, no need... just the seawater, in the 10>
My display water parameters are all good (0/0/15 nitrate), fish are happy, Halimeda is growing like a weed (damn stuff), so it has not had an adverse effect yet, but I don't want to be hasty and ruin things.

Thanks, as always, for your time and efforts!
Chris
<Welcome! Bob Fenner>

Submerged Motor Assembly of Magnum 350 11/18/11
Hi.
<Hello Stephanie>
While doing our first partial water change on our 90 gallon tank we got a couple of weeks ago I ran into a disaster. When I turned the pumps back on I didn't feel any water coming back in from the return line. So I stupidly thought that I had to re-prime the pump so I unclipped one of the clips and water starting flowing all over the place a couple inches on the floor before I could get it stopped and the hoses out of the tank. In the chaos of putting the filter in a bucket to help with the water I didn't notice till after that the pump assembly had fallen off into the water. I tried drying what I could with hair dryer and tried to use it but it didn't turn on. So I'm air drying it now. Is it shot or do I need to buy another pump assembly or do you think blow drying and air drying eventually get the water out if there is any left. I can't believe how stupid this adventure was but I guess you learn from your mistakes. My first time with canister filters. Sorry for such a long email.
<Ah, panic set in here. Let me first say that the Magnum motor and switch assembly are sealed units so the motor itself should have no water inside. I'm thinking the Magnum canister needed to be burped. You can find this procedure in the troubleshooting guide in your manual. Another item to check is the impeller assembly, make sure the entire assembly is installed correctly as shown in the manual.>
Thanks for any advice you might have.
<You're welcome. James (Salty Dog)>
Stephanie
Re Submerged Motor Assembly of Magnum 350 11/18/11- 11/19/11
Hi.
<Hello Stephanie>
Thanks for getting back with me.
<You're welcome.>
I tried again after a let it sit outside for awhile in the sun. It is working. Though what got me to open the lid in the first place was the water flow wasn't coming out. It is coming out now from the return but not very fast.

To be honest I don't how fast it is supposed to coming out or anything about it we bought the tank used a couple of weeks ago with the equipment included.
<The Magnum 350 is rated at 350gph.>
We do have a couple of biological filters hooked up too.
<To the Magnum?>
Thanks for information.
<Welcome.>
Hopefully I will never have a flood again from doing something so stupid.
It would of been a quick way to drain the aquarium but we just finished putting clean water in.
I do have one more question since you've been so helpful. I have a 125 wet dry filter I'm trying to setup in my smaller 60 gallon we bought used and it didn't have all the parts. We have an overflow box but apparently we need an inner box a (prefilter box) to put the u tube to create the siphon. When I look online and in the local pet shops all I've been able to find are overflow box that come with the inner part. Do you know of any place you can just buy that part without buying the whole assembly again.
<Is there a brand name sticker on the overflow box? If so, contact the company.>
I was thinking if I couldn't find one to use a large specimen container and
cut some holes in it for water to get in. Do you think that would work?
<Do not know, worth trying.>
Thanks again.
<You're welcome. James (Salty Dog)>
Stephanie

FLUVAL LEAKS
Hi,
The Fluval external filters (403-404 etc) have received a bad rep due to leaks developing around the main O'ring seal. Having experienced this problem myself with my 404 and 403 filters the cause for the leaks is
simple: During maintenance when the filter is opened; small scratches occur on the inside rim of the filter housing. These scratches then prevent the main O'ring seal from sealing properly resulting in leaks. SOLUTION: get some 400 wet-dry emery abrasive paper and gently polish the inner upper area of the filter housing in the O'ring seating area. I also apply a little Vaseline to the O'ring to keep it supple with no averse reaction to my fish. I hope this helps you.
Stephen
<Hello Stephen. That's an interesting tip. Vaseline certainly can help in situations like this, but the use of emery paper is new to me. I would caution aquarists to be real gentle with the abrasion. Obviously, over time the more that's abraded way, the bigger the gap between the two pieces of plastic. Eventually the rubber seal and the Vaseline won't help. It's a toss up whether repairs like this one would be better than simply buying a new o-ring. Cheers, Neale.>

Fluval 303, op., repair 2/15/10
Hi crew,
<Hello,>
I have an old Fluval 303. It was a second hand filter I received from a friend that used it for years with no problems.
<These are good filters.>
I decided to use it on my 29 gallon tank along with a Aquaclear 50. A few days after setting it up running well, a hose came off the canister and dumped about 27 gallons onto my floor.
<With "old" canisters, the two things to check are the taps and the rubber seal that goes between the canister and the motor part of the thing. If the filter hasn't been used a while, then the rubber has a good chance of having perished, so it's well worth replacing any rubber components before using the thing.>
I was at work and nobody was home to turn the filter off so I have no idea how long it was still plugged in. When I got home I unplugged the filter and the canister was still filled with water. The motor and impeller were stuck in the head when I took it apart to see if there was any damage. I broke the impeller shaft trying to remove the motor so I got the motor out with pliers. I just got a new impeller shaft and the motor doesn't fit into the hole it is suppose to. I'm really scratching my head with this one.
<OK, now, we need to clear up what you mean here. You shouldn't have been able to touch the motor, let alone remove. On most canister filters, the motor is "hermetically sealed" inside the top half of the canister. The impeller is the propeller-like bit that sits in a cylindrical recess in the top half of the canister. The impeller sits on an steel axle that will be slips into a notch at the bottom of the cylindrical recess. Some sort of plastic plate then clips on top of the recess, holding the axle vertically, and stopping the impeller from falling out of the recess. With me so far?
The Fluval 303 also has some sort of plastic insert that slides in alongside the impeller. I'm not quite sure what this is for. Anyway, it's all described clearly on the Hagen web site, here:
http://www.hagen.com/uk/aquatic/manuals/fluve13.cfm
Opening, cleaning, and reinstalling the impeller isn't difficult. But you do need to follow the instructions. You also need to make sure you by the right replacement parts. The Fluval 304 is very different, and parts designed for the one won't work in the other. Again, the Hagen site lists the parts required:
http://www.hagen.com/uk/aquatic/manuals/fluve20.cfm
Their diagram is a bit crummy though, and I found a better one here:
http://www.pondenterprises.com/fluval/fluve4.html
If you used too much force, yes, it's possible to break the axle, but it's more likely you have the wrong sized parts and that's why they aren't fitting together. A really good idea would be to contact a local fish club in your town. There's bound to be someone who's used this very popular filter at some point, and he or she would be able to help you reassemble the thing. Canister filters are generally very low maintenance, long-life items, and Fluval filters are pretty decent mid price filters.>
I'm thinking maybe it got over heated and then melted some of the head but it all looks like its a perfect circle and I really don't know what to do I hope you guys can help me on this I would really appreciate it. Thank you,
Tyler
<Hope this helps. Cheers, Neale.>

Re: Fluval 303 2/16/10
thank you for the fast response and I meant the magnetic motor that the impeller sits on that the shaft goes through.
<Still confused. The metal part of the impeller isn't the motor as such.
The impeller consists of a white plastic propeller thing, a metal axle, and the metal magnetic bit. This impeller unit can be easily replaced. The motor itself is inside the top part of the canister filter. It can't be fixed because it's hermetically sealed.>
Its he original one for the filter I did not replace it fit because I cleaned it and put all new seals in it before I set it up on my tank. The motor fits about half way into the cylinder but then gets very tight and will need to be forced in and once in there is no chance on it spinning.
<Indeed; this would suggest something is either [a] the wrong size; or [b] blocked.>
I have many canister filters and I have never had this problem. I really like the filter even though I am an Eheim guy but this filter worked amazing on my tank and I dont no what could have caused the filter to get jammed and the actual magnet that spins the impeller works. I took a paper clip and put it where the motor works and it spun it and I could feel a magnetic pull I know this is a very weird problem and I understand if you guys have no idea what I'm talking about because I dont know how to word it but thank you for the response so fast.
<It's difficult to know what you're talking about without a photo. If the impeller unit is damaged and won't slide into the recess, then it needs to be replaced. If it's a new impeller unit, and won't slide into the recess, and you're sure it's the right impeller unit for this model filter, then something probably is blocking the recess. A flashlight might show what's inside the recess. Check all the bits of plastic are where they should be.
But without having the thing in front of me, it's really hard to know what the problem is.>
Tyler
<Cheers, Neale.>
Re: Fluval 303
thank you again for the fast reply I brought it to my lfs and the manager came to the conclusion the head of the unit got warped due to the heat when the motor ran without water moving and possibly with no motor. He has another head and another new 303 but I dont think its worth it to buy a new head for it. He is the only fish store I know around here that still has new in box 303's and parts but unfortunately I'm short on cash. thank you for the help and I meant the impellor magnet I'm sorry about he confusion
Tyler
<Yikes! A melted motor sounds pretty expensive to put right. You are correct that the flow of water is what cools down the motor, though whether some other safety feature cuts off the power before they get dangerously hot is unknown to me. I'd be cautious about throwing too much money at a filter in this state, though it's fair to say that the motor is really the only part that wears out, so if you did get a new motor, you could expect a good many years work from the filter. Cheers, Neale.>

Air Bubbles Coming From Hydor Prime 30 Canister Return Hose/Bubble Trouble 11/3/09
Hello,
<Hi Aaron>
I have a 30 gallon tank, along with a Hydor Prime 30 and a SeaClone 100. I have managed to "fine tune" the air valve on the SeaClone so there is no bubbles coming from that. However I am getting bubbles that randomly shoot out of the return hose. They are small, fine bubbles but they are very annoying. I have repositioned the return hose in many ways, shortened the inlet and outlet hose, verified there are no kinks or leaks. What can I do to fix this issue? Please help!
<It is very unlikely the problem lies with the return hose. Check the drain hose connection at the filter for a good seal, and also the "O" ring seal on the pump housing.
Carefully remove the "O" ring and inspect for cuts, clean out groove with a toothbrush, then clean and apply clear silicone lube ("O" ring lubricant by Lifegard) on the "O" ring. This should take care of the problem. Also check for obstructions in the drain line to the filter and be sure the intake screen is free of debris.
<James (Salty Dog)>
Aaron

Eheim 2028 losing prime\sucking air 4/23/2009
Hey Guys,
<Hi Wes.>
My name is Wes, I just purchased an Oceanic 120 gallon tank, I chose the Eheim 2028 canister to filter this tank.
<A good filter. Will last years with proper maintenance.>
After I put everything together, I started the system, and found that when I try to put the water flow to the
maximum setting, It starts to get air bubbles in the intake line, then stops cycling the water.
<Hmm, you have an air leak somewhere in the intake.>
The pump continues to run, but the water is not flowing through the tubes.
This unit also came with aftermarket intake and spray bar.
made by Eheim which I have installed.

When the unit stops cycling the water, I can push the primer down a few times and the unit will cycle for about ten seconds then stop again.
<Priming freed the airlock on the pump.>
This unit also has a flow rate indicator on the return. When I put the flow rate to max the indicator turns completely orange (meaning the system is blocked). I have taken the media baskets out two times now to ensure that the intake tube is positioned correctly (which it appears to be). Could it be that the aftermarket pieces are causing this problem?
<Seems to be - I think you have something not set up correctly - missing or rolled o-ring.>
What other suggestions do you have to rectify this problem?...
<Take the intake apart and make sure everything is assembled properly.
Look for any physical defects in the tube as well.>
Any advice would be greatly appreciated. Please keep in mind I have never dealt with a canister filter before..:) Thanks for any help you can offer!
<My pleasure>
<Mike>

Re: Eheim 2028 losing prime\sucking air 4/24/2009
<Hi Wes>
Okay...found the air bubble problem...I had a rolled O-ring at the top of the intake tube (good call on that one by the way! ).
<Thank you.>
The filter runs continuously now, but when I try to put the water flow on max the water flow indicator still goes orange indicating there is a blockage.
The filter is still cycling fine, just with the orange indicator. Could this be because the spray bar is about 2 inches under the water, so the flow meter is registering this added pressure?
<Bingo.>
Again any advise would be greatly appreciated!
<In my 150 gallon FOWLR, I removed the spray bar entirely. and just had the elbow just under the surface of the water. If you want to keep the spray bar, do get it closer to the waterline.>
Thanks
<My pleasure, Mike>

Broken Canister Filter 1/22/09 Hi WWM team <Hello Dan> I love your site, it is extremely helpful. <Thank you.> My question... I have a Fluval 403 and the motor died. I know it's not the impeller or anything like that... it's the electrical cord connection. <The connection at the pump or the wall end?> Anyways, the filter maintains a good seal with no leaks. Since I don't have the $$ to replace it, I was wondering if I could connect a water pump (I have a mag drive and a ViaAqua lying around) just after the output, as long as it is about the same flow rate? Shouldn't this achieve the same result?...pumping water back into the tank. <Likely will not be worth the effort as the replacement pump would be a good distance from the outlet of the Fluval. This will make it difficult for the pump to draw from the canister and likely will cause cavitation of the pump resulting in a flurry of micro bubbles in your tank. I'm thinking you are going to have to create a siphon by drawing on the end of the outlet hose and then plugging in the pump. Not something I'd want to do on a regular basis, and, even it it worked, it would discourage you from cleaning the filter when needed. You would be better off looking for a used filter on some of the forums. Most are willing to sell at very reasonable prices.> Thanks so much! <You're welcome. James (Salty Dog)> Dan J <<James... why not suggest replacing the cord? RMF>>

Upgrading Filtration 12/10/08 Hi, <Tina.> I have a question about maybe upgrading a canister filter. I have a 90g euro braced acrylic tank. Here is what I have. 175 lbs live rock, 60 lbs live sand, Aqua C remora protein skimmer, magnum 350, Rena xp3 canister, Hydor Koralia 3. Here is my problem/question. Here is the situation. Started tank with live rock & sand almost 2 years ago. Happily added fish & LPS corals over a year. Nitrates went up to 20, did water changes, talked to www crew, too many fish, took out 1/2 of them, nitrates now at 20 after 20g water change down to 10 over a week back up to 20. Fish load: 1 jaw fish, 1 flame angel, 3 green chromis, 1 6 line wrasse, 1 anthis,1 tomato clown, 1 Pseudochromis. other stuff LPS, 1 clam, 1 anemone, 2 shrimp, snails, tiny starfish. November had a problem with hair algae & dying off of a clam, some fish, and most of my snails, again www crew solved the problem. (you guys are sooooo smart.) Anyway today my Rena stopped working after only having it a year. I don't know if I should fix it (have a call in to Mars to see if they know what's wrong there) or upgrade. I know canisters can cause nitrates but I clean it weekly & have only the sponges & white filter in there, I also clean the tubes etc every 6 months. Do you think it is causing the high nitrates or still too many fish? <Your bioload sounds fine from a filtration standpoint. The canister filter is really not doing anything for you at this point, your skimmer and live rock can handle the job.> I started off with the LPS corals but am selling them off because I want sps corals, but I know there is no point until I get rid of the rest of the algae & get the nitrates down to 0. <Not zero, but low and under control.> All my tests except the nitrates are where they should be. Also do I have any time to spare? Without the Rena running (completely took it out, don't want stuff building in the filter or tubes) is my tank a ticking time bomb? <No, but do be sure to supplement the flow the canister was providing.> Should I run down to Petco & buy a canister or do I have some time to order something better? I have thought about either another canister (maybe Eheim), a wet/dry, a sump with live rock, or a refugium. <One of the latter two, or both! If you do go with a sump, consider drilling the tank rather than using a hang on the back overflow. http://www.wetwebmedia.com/ovrflowboxfaq4.htm> To be honest I really thought that the 175 lbs of live rock & 60 lbs of sand was supposed to be my filter but the nitrates suggest otherwise, unless the Rena is the problem (I do 20 g water change weekly). So better filter? <Yes, in a sump/refugium form.> Maybe more live rock & sand & adding more Hydors for circulation & no canister? <Bingo.> Give it up totally and admit I don't know what the heck I am doing? <Don't give up, keep reading and learning.> Any help you can give will be much appreciated. Ya'll are fantastic! <Thank you.> Thanks in advance Tina <Welcome, Scott V.>

Re: Upgrading Filtration, esp. canister f' 12/10/08 Hi, Scott thanks for your quick response to my letter about the Rena filter & upgrading. <Hello Tina, you're welcome.> Turns out the Rena xp3 just needed a impeller. <Not uncommon.> But now you have me thinking instead of investing in a sump can I just take the baskets/media out of the Rena & fill it with small pieces of live rock? Big enough of course not to obstruct the flow. <You could do this. Once you go sump you will never go back!> I don't know if you have to have a open sump to off gas or not. <It is better to have an open top. The increased surface area is one of the benefits of a sump.> Or if it needs light. <Only if you are growing a macroalgae in there.> Frankly I am not brave enough to drill a hole in a $700 tank filled with who knows (or wants to) how many $$ of live stuff with no other home to save them from one little oops! <Understood. If you use the hang on the back units do be sure to use two, with each one capable of handling the overflow duties on its own in case the other fails.> I have asked for a refugium for Christmas, we will see if Santa loves me or not ha ha! thanks again Tina <We will see. Talk soon, Scott V.>

Rena filter question, can. rep. 11/27/08 I've read through your excellent FAQ on canister filters but have a problem which doesn't come up there. A Rena XP2 filter which has been running happily for three or so years has started to pump intermittently. It will pump as normal for five minutes or so then go off for a few minutes. You can hear the motor just start and stop running - it doesn't sound like air is being expelled at any time. I've checked all the connections, cleaned the impeller, and reprimed thoroughly clearing air bubbles, but none of this seemed to help. Might it be the unit's fault? Cheers Al <Mmm... could be a few things... the more likely is that the impeller magnet is losing its magnetism... Does happen. I would first replace this before junking the entire unit. The next most likely source of cause here is some sort of intake blockage... that is, a "vacuum" on the non-discharge side of the unit... I would remove, possibly bleach/rinse the intake line tubing, thoroughly clean the fittings leading to... and the media in the filter canister... Sometimes this sort of "vacuum" leads the impeller to "fall out of synch" with the motors matching magnetic field. Bob Fenner>

Re: Rena filter question 11/27/08 as a follow-up to this: I've timed the cycle and it seems to fairly reliably go 9 minutes on and 3 minutes off. Bizarre! cheers al <Interesting... one other possibility is some sort of malfunction in/with the motor, the electronics regulating it... BobF>

Re: Rena filter question 11/28/08 Many thanks for your generous advice. I discovered the cause - a buildup of limescale on a heater had caused it to crack, fill with water, and then earth itself through the filter motor, frying it (this morning it was down to 2mins on / 7 min.s off - hopefully that will still have been enough to keep the bacteria in there alive.) <Likely so... and yikes! Glad you weren't electrocuted... I would GFI all circuits that have to do with any/all aquariums... Please read here re: http://www.wetwebmedia.com/gfcimarines.htm> I replaced both the filter (just the power head) and the heater and everything's running nicely again. Fish don't seem too bothered about it and temp didn't drop below 22' so I think I've had a lucky escape. Best wishes, Al <Thank you for this follow-up Al. It's posting/sharing may help many others profoundly. Bob Fenner>

Canister Filter Flow Problems 9/8/08 Hello, I have an external filter and it was working well for about 2 months, but after the 2 months it has been really weak. It used to be able to push the water through 2 plastic pipes (the ones with the holes in so the water can be sprayed out) but now it can only just about do one. I have cleaned the whole filter with new sponges but it is still the same. What could be the problem? If it helps it is a Aqua - Pro 2sp. <Do actually check the lines, run a brush through them to clear any obstructions, along with the water passages in the filter itself. Do also check the impeller in the filter, this may have something wound up in it or just need a cleaning. One other thing to note is that if air is introduced into the lines during cleaning you may need to prime the filter just as if it were just installed.> Thanks <Welcome, Scott V.>

Re: filter... 9/9/08 Hello Thanks for your email. How could I clean the pipes that lead to the tank? Because the two are really dirty an I think that is what is making it go slower. Thanks <Greetings. You can either just flush them through with tap water, or else use special brushes on long, flexible wire handles sold for cleaning filter pipes at aquarium stores. Cheers, Neale.>

Rena Filstar xP4 setup problem 9/25/07 Hi there, <Dave> I just set up a brand new Rena Filstar xP4 filter, but something is wrong and water will not flow through the circuit. <Mmm... likely an air pocket... about the pump impeller itself...> When I prime the filter, the canister fills and air comes out of the outlet pile as described in the manual, but when I switch on after 2 minutes, the motor turns, but no water seems to be being sucked into the filter, <Actually... it is NOT sucked in... gravity supplies this, and it is pumped centrifugally out...> and the outlet hose only fills to the level of the waterline. I can hear the motor turning inside the canister and see the water at the top being stirred around a bit, but nothing else is happening. <Not uncommon> The filter is set up as instructed in the manual, and using the filter media provided. It is located between the minimum and max height below the waterline (~50" below the top of a 21" high tank), inlet and outlet clips, filter box clips and disconnect and pipe joints are tight. All components are new out of the box. <Well described> Any idea what the problem could be and how to fix? <Yes... "carefully" tilt the entire unit a few times... while running the pump... on to its side or even slightly inverted/upside down... this should mix enough water about the volute (the area surrounding and including the pump impeller) to vent the remaining air out... Voila!> I have not been able to find any troubleshooting info on xP series on the www, as everyone says how easy they are to prime. <Canister filters can be the Dickens to prime the first time... Only takes a small amount of air around a well-balanced impeller to end up as you presently are here> Hope you can offer advice, Dave

Re: Rena Filstar xP4 setup problem 9/27/07 Its consternation I'm afraid Bob. <Rats!> I could hardly wait to go home from work to try your advice. I had already tried gingerly tilting the tank from side to side and squeezing the sides to create some pressure to force air out, but had been wary of manhandling the canister with the motor running. <Yes... is heavy, clumsy to move about... and the worry of hose disconnection...> With added confidence, I followed your advice. Some air did come out, but the filter did not spring into action. I noticed that while tipping the unit, I got minor leakage from the seam of the motor housing compartment, and when I took the top off it had water inside. I don't know if that should be, but I guess if there is a route for water to come out, there is a route for air to get in? <Mmm, shouldn't be, no> After that I got rid of the air in the outlet hose, by removing the quick disconnect, opening the valve with my thumb over the inlet and siphoning down the outlet hose. <Good> I also filled the canister to the brim and carefully put the top back on, to exclude air. That did not work either, but I noticed that when I ran the motor, new air bubbles appeared near the top of the canister and an air pocket forms where the motor unit sits inside canister box. <Mmmm> I'm fairly convinced that it should not be this difficult, and that I have a defective unit with an air leak through the top of the canister that is stopping it from operating. Nothing left to do I think, but to go back to the vendor and ask for a replacement. <Yes... but first...> Will let you know what happens and look forward to posting about a working and stocked community aquarium in the future. Meanwhile I will browse your excellent articles demystifying cycling. Cheers, Dave <I would try taking all the hose sections apart Dave... re-fitting them (pushing all back together hard)... and with the ding-dang thing basically empty... try starting it all again... with the intake line siphoning while you use the disconnected discharge line (as you state above) discharging into a bucket... with the pump running. Am pretty sure this is an "air lock" situation (about the impeller) still... that just needs to be purged... IF there is an air leak on the intake side though... this does need to be remedied... Wish I was there physically to aid you... BobF> Re: Rena Filstar xP4 setup problem solved 10/2/07 Hi Bob, <Dave> To tie off this thread I finally found out what was wrong with the filter. <Ahh~!> The unit I purchased was supplied missing a small black cap that covers off one of the ports in the top motor housing unit (not shown in the manual), hence no pressure. The LFS replaced the unit, so I will soon be up and running. <Great!> Thanks for your tips, which mean that I now know what to do if I have any problem with the filter in future when the tank is stocked. Dave <Thank you for this useful follow-up. Will post for others edification. Cheers, BobF>

Re: Rena Filstar xP4 setup problem solved 10/3/07 No worries Bob, <Dave> Actually this problem was a blessing in disguise, otherwise I would probably not have discovered all the wonderful information at WetWebMedia until I had a more serious problem with a tank full of fish. <Ahh!> Just to add that the Rena Filstar xP4 really is very quiet, and had it not been for the missing part, would have been simplicity itself to set-up and operate, so despite my problem I would happily recommend it to others. <Good> I'll follow up on the QC with the manufacturer (now Mars Fishcare) Dave <Real good. BobF>

Noisy Eheim Pro 2028 7/8/07 Hi I have purchased a 2nd hand [had been used for 6 months] Eheim 2028. <A very good product in my estimation: http://www.marinedepot.com/md_viewItem.asp?idproduct=EH2028K> It works perfectly but seems as if air may be present as it 'rattles' when the taps are fully open. If I partially close the taps the noise stops. Is this normal? <No> If not how can I dispel any remaining air? <Mmm, a few ways, but the most assured is likely to turn the power off, disconnect the discharge line, and have it lowered into a bucket, allow the water to drain/siphon through the unit... perhaps while giving the filter itself a few gentle shakes side-to-side to dislodge any air caught in the pump... If you can get a friend to help, watch the lines/water, try turning the pump motor on/off a couple times during this process...> Thanks Alan <Welcome. Bob Fenner> Filter Help, canister with air lock Hi all. I have a Rena XP canister filter(4 yrs old) that will not fill up with water. Usually after I clean it, all I have to do is push the quick disconnect valve down and the filter begins priming. Today that was not the case. I filled the inlet pipe up with water, thinking that it just needed a little more, but it still would not take water in. What is wrong with it? I don't see any leaks. I need to do something quick! Thanks in advance. <Most likely there is a bit of air trapped in and around the impeller (the volute)... this can be most easily cleared by carefully lifting and tilting the filter canister on to its side a few times while the motor is running... Another technique is to pull the discharge line from the tank and let the water run into a bucket on the floor... this will clear the air out. Bob Fenner>

Ammonia and Nitrite Emergency 6/6/05 Hi Crew, my name is Justin and I am having a bit of a problem on the action I should take with the screw-up I just made. I have a 55 gallon salt water tank with a moray eel in it. Since I am a beginner I decided it would be a really good idea to clean my filter (you guys probably know where I am going with this). So I rinsed my Eheim 2028, and all of the media of course, in tap water. From reading on this really helpful website (and lack of common since), I realized I just sent all of my beneficial microbes down the drain. <Hmm... this can be a problem. More because of the chlorine rather than the rinsing itself.> So everything seemed fine for 2 days then BOOM ammonia that was 0 is 1.5 and nitrite that was less than .3 is now .9. I am terrified for my eel, he seems fine, but I'm worried my microbes will not come back fast enough. I have 40 lbs of live sand and 20lbs of live rock I am hoping that they will help. I am sorry if some one has asked a similar question but I could not find it after an hour of searching. Well I hope you can get back to me soon and help me with my problem. Thanks Justin <Your live rock and sand should easily meet the filtration needs of your tank. I would consider removing the canister filter for a more thorough cleaning and monitoring the water chemistry closely. If the ammonia or nitrite get any higher, I would institute a couple of large water changes, but otherwise, let them come down naturally. Best Regards. AdamC.>

Dad's old canister filter... 8/15/05 To Whom it may concern, I have recently inherited my Dad's old fish tank. He has a magnum 220 canister filter. I have taken it apart and cleaned it several times. The last few days it has been spitting out a lot of air bubbles. It has recently been cleaned and all the connections are secure and air-tight. Could this simply mean that the filter is just getting old and needs replacing? It is probably almost 10 years old. Thank you for your insight. Dan <Mmmm, there is an air gap along (most likely) the intake side of this filter somewhere... I would use sprayed water at the fittings, a bit of length of tubing placed next to your ear and at these junctions to see/hear where air is being entrained... I might buy/replace all the flexible tubing (not much money) at the Home Depot, Lowe's... before canning this canister... Bob Fenner>

Canister filter stops running 10/5/05 Hi, and thank you for taking the time to read this. <Howdy, welcome> I have a Serafil 900 canister filter. Recently it switched itself off an stopped running. It's done this before and normally taking it apart, cleaning it and putting it together again sets it in order. That doesn't seem to be working this time however. When I switch it back on it runs for maybe 3 minutes and then just stops. During that time I can hear the sound of water running inside it, which I gather is air circulating around the impeller. I don't think there's a huge amount of air in there though and this hasn't been a major problem in the past. Other than that everything seems to be fine. All the parts fit together well and are all in good condition. Is there anything you can think of that would cause it to just stop like that? I just wanted to check that it's not something that I'm doing incorrectly. Thank you, Dan <The easiest way to prevent this is to fill the canister filter by siphoning through the in line and out the discharge... in a bucket... Once set-up, air-locks can be released by (carefully) tilting/inverting the running filter, upside down. Bob Fenner> Ammonia problem, stopped canister filters 02-05-06 Hello to all. Well have one big problem and I am in need of some advice on what to do. Might have happened to you guys before but this is the first time it has happened to me. I have a 29g TruVu with 40lbs of LR and 3in sandbed of LS. I currently have pair of true perculas, had citron clown goby, and LPS live coral. This mourning when i woke up and turned my tank lights on I noticed that my clown goby was nowhere to be found. I looked and looked for him but he disappeared. I then thought to myself that he must have died because of lack of oxygen because yesterday my xp1 Rena had got clogged with some macro algae that was in my tank but got sucked up in my filter. Yesterday the clown goby was breathing very rapidly so that why I had checked the filter. I thought by cleaning it and unclogging that would fix the problem but it didn't because this morning the goby was nowhere to be found. <Uhh, unclogging the canister filter... you did rinse it out thoroughly before returning it to service I hope/trust> So then I began to look for him. I couldn't find him so my next step was removing the LR piece by piece...And that got me pissed because once I moved all the rock I still didn't find him. Has this ever happened to anyone? If so what did you do? <...?> I tested for ammonia and it had gone up to .25mg/l. Now I for sure know he is dead but can't find it. I do have bristleworms in the tank and also spaghetti worms. Could they have already ate him up? <Yes> Could they have buried his body in the sand to eat? Please help me. I did a water change and it did seem to help but I still have a feeling the ammonia will continue to go up again? Any advice in what I can do to fix this problem? <Time going by at this point> ...I have had my tank for over a year now so I know I am past the cycling stage. Never have had this problem with ammonia ever. I moved my clown fish to my QT but am scared to lose my corals! Help me please. Any advice is better than nothing. <The ammonia anomaly was almost certainly caused by the plugged then unplugged canister filter... causing the demise of the goby... perhaps the worms eating it. Bob Fenner> Equipment/Filters...Bursts of bubbles from a Magnum 350 5/25/06 Bob, <James today, Bob exploring the mysteries of the deep in HI> <<Heeee! RMF>> I noticed the question from Donna regarding air-bursts from her HOT Magnum. I have been using three 350's and two HOT's for several years and the only time I observed air building up in the canister (and causing bursts of bubbles) was when I had an airstone near the intake and it would suck in the occasional bubble until a larger bubble was built up inside the canister. and then it would periodically spew a mist of air droplets in the exhaust several times a minute. This sounds like it would have been obvious to the most casual observer, but it took me several days of messing with everything I could think of on the Magnum until finally I was glaring at the snorkels in frustration and saw a bubble spiral around into the intake side. (D'oh!!) Using 5 Magnums for the last three years and that's the only way I've seen air get entrained - through the intake. <Thank you for this, Mark, will post. James (Salty Dog)> Mark Hein

What's This Spewing From My Canister Filter?...Bacterial Film - 07/25/06 Good evening WWM crew, <<Hello Lorri>> I have spent the better part of today researching my most recent quandary about my new (3 month old) 40 gallon marine aquarium. My husband is starting to growl about not getting dinner, so I felt it was time to ask my question directly to you...the experts. <<Mmm, yes...must maintain the peace at home <grin> >> Today's question is basically this: Why does the output tube from my Fluval 204 spew copious amounts of opaque junk (looks like small pieces of uneaten raw shrimp) back into the tank after I have turned off the canister to clean the filter and then restart the filter according to manufacturer's instructions? I am obviously doing something wrong. Just not sure what. As always any input would be appreciated. <<You're not doing anything wrong, nor is this anything to be worried about. Your filter's output tube (indeed ALL your tank's plumbing lines) gets coated with a filmy mat of bacteria. This is a natural occurrence and one reason we recommend over sizing plumbing lines a bit to allow for the decreased flow that occurs as the material builds on the inside surfaces of the plumbing. These mats grow in relation to the pressure/flow direction of the water in the filter/plumbing lines. When you stop the flow, the bacterial mats "relax" a bit and when the flow starts up again bits are torn away and these are what you see exit in to your tank. In my experience these "bundles" of bacteria/bio-film are harmless and quickly dissipate in the tank>> By the way please share my good news with Mr. Fenner regarding the Purple Long Tentacle Anemone whose tentacles were slightly burned when they came in contact with some diluted marine buffer I had added to the aquarium "she" has made a most spectacular recovery and appears beautiful and healthy again. I now add the buffer during water changes per his advice. Thank him for his reassurance. <<You just did...am sure he will see this>> Lorri Thanos <<Regards, EricR>>

Bubble/Cyano Issues - 08/22/06 Greetings from Grayslake, IL <<Back at you from Columbia, SC>> I've read a lot (I won't say all) of the FAQs regarding bubbles but I am still running across an issue. <<Ok>> Here is my set up: - 29 gallon reef tank up and running for about 8 months now - CPR Bak Pak - Magnum 350 Canister Filter - 2x96 Watt 10k PC (On for 7 hours) - 2 actinic bulbs PC (On for 10 hours) - 40(+-) lb live rock - 2-inch live sand - RO/DI 4-stage system Here is my problem. I still get bursts of air bubbles from the canister filter. <<Hmm, air intrusion from somewhere...builds up to the point where the bubble is large enough to "escape" to the outflow/impeller chamber of the filter pump...thus the "bursts" of bubbles>> I have broken down the system and have replaced the o-rings and have added metal clamps on the all of the hoses to try to tighten it all down. Can't really find any leaks in the system. <<Have you tried "sealing" all the joints one-at-a-time with Vaseline? <Mmm, would not use a Petroleum-based material... too likely to act as a solvent... soften the tubing in the long/er run. Perhaps a Silicone-based lube. RMF> Have you checked to see if bubbles are being generated/pulled in to the filter through the intake from the intake water chamber (sump?)?>> In addition to the bursts of air bubbles, when the lights are on I get a small amount of bubbles constantly. <<Check the placement of the filter intake/the possibility of bubbles in the surrounding water being pulled in to the filter>> Suggestions? Replace it? <<Might be worth a try>> What would you guys/gals recommend for a replacement? <<I've always had good luck with the Fluval line of canister filters...and if you have the bucks, Eheim is a good choice>> I am also getting some muck on the top of the sand when the lights are on but it is gone when the lights are off? <<Cyanobacteria...possibly>> Some of my live rock has turned red on the tips, don't think that it is coralline algae. Some form of algae was wondering if I need to be concerned here or not. <<Hard to say...likely not. But do have a look through our FAQs/articles re "Cyanobacteria" and "blue-green algae">> Thank you for your time. <<A pleasure to assist>> Like everybody else...Love the site! Very very informative. <<Always good to hear...thank you>> Sincerely, Richard Hunt <<Regards, Eric Russell>>

Re: Bubble/Cyano Issues 8/22/06 Thanks for the reply. <<Welcome>> I am not running a sump, just the CPR Bak-Pak and the Magnum Filter. Regarding the Vaseline... <Again, NO to the use of Vaseline... IS a SOLVENT. RMF> how is that done? Do I pull out the connections and add it to the connection or to the hose? <<No need to pull apart the connections...just smear some around the "above water" connections to seal them temporarily. Do this one at a time watching each for a bit to see if the bubbles stop>> The intake is behind a piece of live rock, so I don't really have any air coming from there I don't believe. <<The steady stream of air bubbles while the lights are on could be nitrogen bubbles from your rock/substrate being sucked in to the filter intake>> Again, Thank you Richard Hunt <<Regards, Eric Russell>> Re: Bubble/Cyano Issues - 08/22/06 Now that's interesting. I do have tiny bubbles all over the red stuff on the rocks that I spoke about in my original post. Could that be what is getting into the filter? <<Ah, most assuredly Cyanobacteria then...and yes, the filter intake could be pulling-in these bubbles>> If so...how do I get rid of the bubbles from the live rock? <<Increased water movement often helps when battling this blue-green algae. Do have a read here and among the links in blue for much more information: http://www.wetwebmedia.com/bluegralgae.htm >> Thanks, Richard <<Quite welcome, EricR>>

SW canister filtration 12/6/06 I have been reading over your site and now realize I may have to change my filtration. You almost always recommend a sump for all salt tanks... I have 2 Eheim canister filters on a 75 gallon with an aqua c remora pro skimmer. In the Eheims I have the white filters, blue filter, Chemi-pure and the ceramic rings. Would this be ok with weekly maintenance? Or will my water quality eventually become poor due to inadequate filtering? Any suggestions you have would be of great help. < With diligent maintenance you can avoid common problems associated with canisters, but the main concern is a power outage. These filters can become anaerobic in a short time if power is lost, and pump some really nasty stuff back into the tank when the power is restored. If you have enough live rock you can remove the canisters, albeit one at a time over a few weeks. You can also keep a canister to place your chemical filtration in as long as you clean it out often. > Thanks < Most welcome and best of luck - Emerson >

Rena Filstar Issue... air leak 1/31/07 Hi Guys- <Howdy> I have a 300 gph Rena FilStar canister filter which has been functioning beautifully for about 6 months. Over the last few days the water level in the canister has dropped and every 2-3 minutes, there is a sucking sound and a whoosh of aire entrapped in water is jettisoned out through the out let hose. It creates quit a horrendous sound. <Yes... you have an "air leak" somewhere on the intake side of your plumbing> Have I lost my seal on the filter? <Yes> How is air entering the canister? Whats the remedy, new o ring, or a new canister filter? T Joe Tremper <Mmm... a careful examination (possibly with a length of tubing against your ear, other noise turned off... and/or a squirt bottle with "just water"... to try and detect the leak... starting from the intake from the tank... to the canister itself... Perhaps a systematic disassembling, trimming of "old" flexible tubing, re-fitting to the hard plastic couplers/els... maybe the addition of a bit of smears of pure Silicone lubricant to seal all a bit easier... including the top/O-ring... Good hunting! Bob Fenner>

- Broken Fluval? - I have searched and cannot find a solution. My Fluval 404 isn't running correctly. It seems that the return water flow is half of what it normally is. I cleaned the impeller and am at a loss. Any suggestions would be greatly appreciated. <Do go through all the tubing and intake screens as well... look for possible obstructions, otherwise contact Hagen directly.> It is a few years old. Motor sounds fine. Thanks in advance Lisa <Cheers, J -- >

Fluval Emergency Hi. I think I may have made a catastrophic mistake this morning. I walked by my 55 Gallon FOWLR tank this morning and saw my Fluval 304 canister filter was unplugged. Without thinking, you guessed it, I plugged it in. Well it only took about 30 seconds for the rotten egg smell of hydrogen sulfide to hit me in the face. I was crushed as I didn't think of that possibility before as well as I realized there was no turning back once I made that crazy decision to plug it in. I turned the filter back off and cracked it open and it was very black inside. I just got back from vacation a few days ago and everything was fine so I don't know how the filter got unplugged. I have a few questions. First, I threw everything away that was in the Fluval (foam pads, activated C bags, ceramic Biomax, and PolyFilter) and added a fresh 100 g bag of activated C, a whole pad of Polyfilter, and fresh foam pads. I also started preparing 14 gallons of water to do a 25% water change when I go home. Is there anything else I can do. How much C would be reasonable to run; should I add like 6 100 gram packs to the Fluval or just run one? And the two questions I hate to ask. Is it almost certain death to my fish since I actually smelled the gas coming out of the water, and will the sandbed and 50 lbs of LR in my tank be garbage now or will the H2S not absorb and contaminate for life? Thanks for the advice as I want to save anyone I can. Ray <Hello Ray, The first and best thing you can do is a large water change obviously, in the range of 50 percent. You didn't mention if this canister filter is the only source of water circulation in your tank, nor did you mention how long it had been off. Those are two rather important pieces of information. Your rock is probably fine, and in all likelihood so is your sand bed, but again I lack some vital information. If your fish are still swimming when you get home, then they'll be fine! For all the talk of hydrogen sulfide gas, I've never seen it whack a fish myself. That doesn't mean it hasn't happened, but in my experience I've never witnessed it. Run as much carbon in your canister as you wish, there is no right answer there. If your sand bed is dead, then all the carbon in the world will not help you, and you'll have to pull it. If you've had power heads or a return pump circulating the water all the while, your sand bed is most certainly just fine. Cheers Jim>

Fluval fix Hi Wondered if you could help. I have a Fluval 304 about 4 yrs old. It always ran fine until the other day. I clean it once a month basically replace the carbon and rinse the foam. I use it more for chemical filtration as I have a Bio-Wheel and Aquaclear on the tank as well. I also like it because of the flow it gives me as well. Anyway I stripped it down and put it back together as I have done a hundred times. I put it back under the tank. When I came home at lunch the following day the water in the tank was down about 1 1/2" ( its a 65g by the way). I thought it was the tank but after some investigation I discovered it was leaking from the filter. There was a steady drip of water running down from the blue handles on either side. I thought it might be because I had filled up the baskets to the top with some carbon and pre-filter material more than is usually in there and it was restricting the flow of the water through the filter in some way. I took out the extra material and returned it to how it was before but this didn't fix it. I then thought it might be the seal for the motor housing so I have just run down to the LFS and replaced that but that isn't working either. I will try to describe where the water is coming from. Where the two parts lock together all the way around there is a kind of bulge well on the part where the handles are it kinda flares out and creates a well next to the handle. At the top of these wells there are small holes and that is where the water comes from. The canister part of the filter not the motor housing. I hope you understand and can either help me or let me know who can. Thanks PS - I sent in a question about 3 weeks ago and didn't get an answer. No biggie I solved that problem now but would really appreciate an answer to this. < I had a guy at work with a similar problem and he asked me to take a look at it. I think the problem is with a dried out O ring that seals the upper and lower pieces together. I never got a chance to try it but I think if you grease the O ring with a white grease or even try some petroleum jelly you may have some luck. I know that he had called the company rep and got no answers and I never talked to him again to see how it turned out. I think he just bought a new filter from a different company.-Chuck> Dean K. Smith

Re: Leaking filter, FW Thanks for the prompt answer. I replaced the seal with a new one yesterday and the leak slowed down a little but didn't stop. So I called the company today ( I am in Canada by the way) and as soon as I told them the problem the told me to return the filter for repair. They seemed to know exactly what it was and weren't concerned that the filter was no longer under warranty. Seems to me this must be a common problem with this filter. Anyway they told me to send it to them at my cost they will return it in a couple of days at there cost. Hopefully it turns out well and I am glad I am also running another filter on this tank. Thanks again for the quick response and keep up the great work with the site I visit everyday. < When it comes back please write and let me know what they did. thanks.-Chuck>

Leaking Fluval Redux Well I got my filter back today. It all seems to be in order and working fine. I checked over the filter before I started it up again and it seems the only difference is a new type of impeller cover. It seems a better fit and has a fitting that looks like it prevents the impeller from sliding out of the well ( I had a problem with that). I wish they had sent a replacement though because it is very difficult to unclip now and I can see myself maybe breaking it down the road. They stated that they replaced the impeller, the impeller shaft, the impeller cover and the O-ring and they also tested the unit for 24 hrs at no extra charge to me. The impeller was only about 3 months old and the O-ring was brand new. Overall I would say I am satisfied but not impressed as I was a little ticked that the turn around time was 6 days instead of the 3 that they stated when I called them. But anyway the filter is back on the tank and both the fish and I are enjoying it working properly Hope this is some help as I visit the site everyday and would like to give a little back lol < Thank you very much for the reply. It has helped me and hopefully it will help others checking the site.-Chuck>

O-ring problem Hi, I want to start by saying I am really glad I found your site today. I learned a lot more since finding it than I have in the short 6 months since I found out that I am nuts for this hobby. On to my question. With my wife out of work, I am on a very tight budget. I wanted to get a larger tank to go with my 10 & 20 gallon tanks, and kept an eye out for a "garage sale special" After looking out, I picked up a 45 gallon tank, stand, filter & Heater for under $100. The filter is a Chinese no-name brand canister filter, but definitely works, as I am familiar with the former owner and his Flowerhorns. The name on it says "Sun Sun", but I can't find any info on them. Like I said, no name Chinese made. It looks like the o-ring gave out, and was hoping you might know a DIY resource for O-rings.<Chris, look in the yellow pages under bushings/bearings. Most of these places have a huge assortment of O rings. Take the part of the filter that has the O ring with you> James

Canister filter losing prime If we lose power and then it comes back on the Fluval will not start pumping water. However the motor is running, have to shake the canister to get it to start. Any thoughts on how to fix this? Thanks <You have some/an air gap... some gas trapped in the canister or flexible tubing... that is accumulating in the motor/impeller when all is turned off... You need to invert, right the canister a few times to discharge this each time you have the filter apart... and learn to prime it completely when re-starting it... by lowering the discharge line... Bob Fenner>

Canister filter emergency Hi Bob! <You reached Steven Pro today. Anthony Calfo and I are helping out while Bob is away.> I just discovered that my Eheim 2215 canister filter has not been running, probably for a week or more (the plug was loose in the socket; it looked plugged in but wasn't, and the pump normally runs so quiet that it took a long time to notice. Pretty dumb.) How do I go about cleaning the gravel so that it can function as a biological filter again? Do I need to drain the hoses that connect the filter to the tank, since they're probably filled with yucky water? My 55-gal tank has a CPR BakPak skimmer with bio-bale, and about 70 pounds of live rock, so it's not totally without filtration, but of course I want to take care of this right away. Thanks for your help! -Suzanne. <Clean and drain everything in the Eheim. It will probably smell something awful (similar to rotten eggs) if it has been off for a week. -Steven Pro>

Re: canister filter emergency Excellent advice... but how exactly do I go about cleaning the gravel?

Filter blockage deaths Hi Bob, I went on my honeymoon for 2 weeks. <Congratulations> during our absence the filter tube fell causing it to kink and block. The person we had looking after the fish came in and found the fish dead (Picasso trigger, 2 clowns, 4 stripe, emperor angel and blue tang). It had been 6 days since they had last seen the fish. We had an auto feeder set and all was OK up to then. (We had introduced the feeder slowly making sure the fish were OK to eat dried food and that the feeder worked OK over an extended period of time). <Oh> I returned 3 days after the fish had been found and by then the filter tube had been unkinked. All the chemical measurements were normal. What would cause the fish to die? Could they have died by lack of oxygen? A number of small crabs (2cm) and worms that were living in the live rock were also dead. The anemone also died, however one large coral has remained alive. <Many changes could, might have occurred as a consequence of the "kinking"... low dissolved oxygen for sure... and with con/subsequent changes in loss of aerobic nitrifying bacteria... and, and, and...> This is the first time we have lost any fish since we started about 6 months ago and we are very upset. How would the fish have died and would they have suffered. <Not likely to have suffered. Aquatic life is "hard-wired" differently than tetrapods (e.g. birds, mammals).> Regards, Michael. PS. Thanks for your website. There is much contradictory advice on SW aquariums, but we usually take your advice. <Thank you my friend. Don't be discouraged with these accidental losses. Make provision that it cannot recur and go on. Bob Fenner>

O rings (Tetra repair part) I have a Whisper power filter- Model 2B- the O ring leaks water. Can you tell me were I can get new ones. Thanks, C. Herbst

Problem with Fluval 204 Canister Filter Hello, and great site by the way. <Thank you very much. I am sure Bob appreciates all the compliments he gets.> I've got a new freshwater setup. A 100 Gallon Tank about half full for a VERY lucky Red Eared Slider (Turtle). Everything is working great for this little guy, but I've had a bit of trouble with the Fluval 204 Canister Filter that I bought for him today. The filter seems to be constantly developing air bubbles and is difficult to prime. It is an intermittent problem. Sometimes the filter will go for hours without a problem, and sometimes it's only a few minutes. I have the filter mounted level with the tank because of space restrictions. My basic questions are: 1.Does the placement of the canister cause difficulty in filtration? <Yes, it should be well below the tank water level.> 2. Is it normal for this type of filter to have this much trouble with air bubbles? <It is common for Fluvals to have problems purging the air when the sponge filters are new. They hold a lot of air and it takes awhile to force it out. Also, your height differences maybe making the problem worse.> 3. What kind of media would you recommend to keep this ammonia producing monster from poisoning himself? <Activated carbon, Zeolite clay, and the ceramic rings.> Thanks for your time and effort in putting up such a comprehensive source of information for those of us that are "Aquatically Challenged" Eric <You are welcome. -Steven Pro>

Re: Canister filter question Thanks for your quick response. Okay, I understand and will probably take your suggestion. But just to further my education what would be the harm in allowing that filter to act as a biological filter as well? Could I add half of the recommended media? So there would be less surface area. Finally how often do you clean out a canister filter's media if it is a bio filter? -Pete <It is unnecessary to use as a biological filter if you have sufficient liverock and live sand in your micro reef tank. It will breakdown certain compounds making it more difficult for your protein skimmer to remove them, adding unwanted nutrients to your system. The media will displace more water and will eventually get dirty and cut down on the flow rate from the canister filter. -Steven Pro>

Priming Canister Filters I have a Fluval 404 filtration system for my 185 gallon aquarium and can't seem to get it pumping. Motor is running . do these have to be left on for a while to start (primed)? <Don't have to be left running (go and turn off NOW!) w/o water in them... you have to prime this canister filter... suck on the discharge end over a bucket to fill the intake line and canister itself... THEN plug it in. Bob Fenner>

Filter Problems (canister, marine) hey... I don't know if you guys are familiar with filters... but my filter won't suck up water anymore.... can you tell me what the problem is... its a magnum filter... the old ones.. not the new 350... but yeah... it won't suck up any more water... I checked it many times.. the only thing wrong with it is the rubber band which is on the cap... I asked a man about it and he said that the because the band has little breaks on it that it would let in air.. would air affect the filter's ability to suck the water... I mean at first it works... but only for a few seconds.. the water level in the filter starts to lower, then at about halfway emptied it stops sucking in anymore water... can you help me out... I know it's not a fish problem but.. any help is fine... thanks... Sokha <You should replace your gaskets. -Steven Pro>