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FAQs on Fluidized Bed Filtration

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Related FAQs on: Biological Filtration, Ammonia, Nitrites, Nitrates, PhosphatesDenitrification/Denitrifiers, Wet-Dry Filters, Bio-Balls

According to Bob at Aquatic Specialties, this FB filter can handle 8-10,000 feeder comets.

Sea Storm Filters 11/23/11
I am trying to locate a Sea Storm filter like the one you have pictured on your site, the larger square clear acrylic one.
<Can you link me to this picture?>
My dad was the original creator of that particular model. Any help in trying to locate one would be greatly appreciated.
<Will this help?
<You're welcome. James (Salty Dog)>

Fluidized Bed Design/Fluidized Bed Filters 10/28/10
Hello from Japan.
<Hello James>
I have been toying with the idea of building a fluidized bed reactor for a 50 gallon tank. Currently it is filtered by a trickle filter with bioballs, Beckett skimmer, coil denitrator (feeding 1.8ml of ethanol), and Rowaphos in an old Coral Sea calcium reactor which is now converted to work as a fluidized bed <filter>. Even with this, I manage to have algae grow on the glass, requiring removal every 4 days. Lighting is 3 150W MH units (2 20000 Kelvin and 1 14000 Kelvin unit) that are on for 10 hours a day. Water temp is 23.5 C. No measureable ammonia or nitrite. Calcium is around 400 ppm and dKH is 12 ( I use Dr. Farley's bionic solution
<Not familiar with that product.>
plus a small calcium reactor powered by a not so reliable yeast generator).
I have read that FSB reactors when designed properly can provide both aerobic and anaerobic filtration, but that it requires height. Is there any rule of thumb as to how much depth is required to establish anaerobic bacteria?
<Fluidized Bed Filters are designed so that all of the sand/media is tumbling. In that regard, it would be impossible to establish anaerobic bacteria in a fluidized bed filter as these bacteria only grow in areas of little to no oxygen. Fluidized bed filters never gained much popularity among marine aquarists as there are more efficient means of providing denitrification;
notably with live rock and wet/dry filters. You may want to read our FAQs on this subject by going
here. http://www.wetwebmedia.com/fluidbedfaqs.htm>
<Ditto. James (Salty Dog)>
James Miller

Re: Canister filter media order, now fluidized bed, Si issues questions  4/30/10
<Hi Gary.>
When I said my fluidized filter dumped sand in my tank and would it be leaching silicates, you replied
Perhaps - only time will tell unfortunately. Can you elaborate on this, what could happen.
<If you get a sudden dump of silicates, you can get a diatom algae bloom.
Not really harmful, but it takes time to clear up.>
< http://www.wetwebmedia.com/diatomfaqs.htm >

Fluidized Bed Filter Removal 1/13/10
<Hi Gary>
My tank is just about 5 days into its cycle, no spikes yet.
Can you tell me if I should remove my Fluidized Bed Filter, as I have been reading on the database some not so good things about them, and if so with only 24 pounds of live rock will my tank be sustainable. This question is nothing to do with the cycle, its just a general question of the pros and cons of a bed filter.
<With your Live Rock/Sand, the use of the bed filter isn't necessary. I would get another 15-20 pounds of live rock if room permits.>
40 Gallon JuweL Vision 180 with internal filter removed.
24 Pounds of Live Rock.
20 Pounds Coral Reef Live Sand.
Lifeguard FB 300 Fluidized bed filter.
Protein Skimmer with a needle wheel venturi pump flow rate: 1850 L/H.
Wave Maker 6000L/H Powerhead.
Wave Maker 3000L/H Powerhead.
MaxiJet 600L/H Powerhead.
<Mmm, if your above figures are correct, you have an awful lot of flow for a 40 gallon tank.>
Thanks in advance
<You're welcome. James (Salty Dog)>

Re Fluidized Bed Filter Removal 1/14/10
James (Salty Dog),
I've checked my pump flow rates and they are as stated 3000L/H and 6000L/H, they are both Sun Sun models and after looking at reviews and forums some people prefer them over Koralia, anyway back to the point do you think I should remove one of them or not, the thing is I bought big to get a good flow around my Live Rock because I have read you can never get as strong as the sea anyway in terms of flow. To be honest they don't actually seem as powerful as stated my sand isn't blowing all over or my Live Rock, I would like your opinion though as I value it.
<If they produce a similar flow (diffused) as in the Koralia, I feel from personal experience that even then it's a bit much. I have a 60" x 18" tank and equipped it with three Koralia 3's and I had a sand storm. I might add that I have a shallow tank (18") which would make the flow more turbulent. Taller tanks would likely calm down the flow some. As long as your fish aren't hanging on the rocks for dear life, and your corals don't look like my hair riding in a convertible, then go for it. I'm guessing from your information that you are using a wavemaker of some type whereas the pumps alternate.>
I have a stock list I would like you to look over and tell me if is viable with the set up I have with the amount of Live Rock I have at the moment, although this obviously won't be happening for some time yet.
2 x A. Ocellaris or A. Percula
1 x Royal Gramma
1 x Dwarf Angel (Centropyge argi) <Centropyge, and not appropriate for your size tank.>
1 x Watchman Goby
1 x Pistol Shrimp
<I would add more live rock before adding anymore fish.>
<You're welcome. James (Salty Dog)>

Use of aragonite in fluidized sand filter, shark set -up f' as well  9/1/08 Hello Guys, <Brian> I have a question regarding the use of aragonite sand in a fluidized sand filter for a marine Elasmobranchs pond setup. <Mmmm> Are there any drawbacks to the use of aragonite sand in fluidized sand filters as opposed to the sand that comes with the units (ie silica sand)? <Yes... mainly the pumping action (energy) it takes to keep this asymmetrical, different size media in suspension, turning... otherwise issues from channeling... from insufficient water movement> Is it a good idea to use aragonite as opposed to the supplied sand? <IMO/E, no> I greatly appreciate your time in reading and/or answering my question. Your website is a tremendous asset. Thank you, Brian <It would be a good idea to have a "monster size" DSB composed of aragonite, for buffering and anaerobic activity... but the FB is an area/processor of the forward reactions of nitrification. Bob Fenner>

Re: Lighting and pump selection questions 12/5/07 What about ditching the trickle filter (via sump and bio balls or bio bale), and attaching fluidized bed to the sump. Considering price of bio balls, really isn't much of a jump to the fluidized bed. <You could, this could theoretically decrease your CO2 out gassing.> I also hear that because they agitate some much, the detritus accumulation will be almost nil, <Ideally with some sort of mechanical filtration first. You will end up with a layer of detritus in the fluidized bed, probably floating on top of the media. It would get accumulated by the bioballs anyhow. You will be able to siphon it off in the fluidized bed.> necessitating cleaning at a rate of *maybe* once a  year. This definitely appeals to me (I am tired of cleaning canister and HOB filters). <Understood, me too. Good luck, Scott V.>

Coris Wrasse comp. and Fluidized Bed Filter  11/6/07 Hello Again Crew Two question if I could? I have a Red Coris Wrasse and was wondering if I could put another Coris Wrasse with him? <Mmm, maybe... the same species... C. gaimard? If they're small, likely so... let's say, under four inches overall length or so> I noticed in the LFS they keep 4 or 5 together. Mine is 4 inches and doesn't bother anyone else in my tank. I love them so colorful and bullet proof. Never has gotten sick and has lived through ick and velvet outbreaks in the past and never got it where everyone else has. I was thinking about getting a yellow Coris wrasse to go with him. <Oh! this is actually a Halichoeres species. H. chrysus... will likely get along if there's room...> The LFS always tells me things will get along and then I get home and someone getting beat up. Second question. I was thinking about adding a fluidized bed filter. I read on a company site if you slow down the flow you can turn it into a nitrate reducer. <Mmm, not likely> I know they sell ones that are similar in design for reducing nitrates and was wondering your thoughts on it? The FBF seem like a great filter and Am not sure why I haven't seen or heard more about them? Is there a drawback I missed compared to a wet dry? Thanks Crew! <A few... these FB devices are engineered to be more like wet-dries... with their media in constant upheaval, agitation... I encourage you to keep reading re marine filtration methods for now... consider adding a sump/refugium... with a DSB there... instead. Bob Fenner> Re: Yellow Watchman Goby... Actually BGA, FBS- 09/17/07 I have your book "The Conscientious Marine Aquarist" I read like crazy, I have only been in the hobby for 2 years. The octopus got me really hooked. It is a shame I can no longer acquire them in Brazil because of environmental import restrictions. I loved her. My first aquarium was a 30 gallon with live rock and sump. This new 75g one is much harder because of the Cyano problem. I had almost no problems with the pus and it is supposed to produce a ton of waste. I now have just 4 tiny fish in 75G. I know compared to where they used to live it is a drop but I thought the larger system would be more stable. Do you think I should ditch the FBF? <I would do this for a month and see what happens> It is home made. I just have the plumbing from the overflow flowing into a small bucket full of oolite Aragonite (maybe 5 pounds) which then overflows into the rest of the sump. I can remove it easily enough. I had the Cyano before I installed it, and it has only been in there a few months. BTW, I take water readings like crazy and read every resource I can get my hands on. This is my leisure activity and I can't get enough. <Mmm, you have read here: http://wetwebmedia.com/bluegralgae.htm and the linked files above? BobF>

Filtration For 55-Gallon FOWLR - 09/10/07 Good Day, <<Hello>> I have a 55gal saltwater FOWLR tank. Currently there is about 25 lbs of live rock, 1-inch of sugar-fine sand, a Whisper 60 filter, a Berlin Airlift 60 protein skimmer, and an Aquaclear 70 powerhead. <<Hmmm...equipment/filtration choices could be better, and there is need for more/better water movement here>> For fish, I have two 1-inch Yellow Tailed Damsels. I plan on removing the 2 damsels and placing them into a separate tank. I would like to slowly add a Saddle Puffer, a Blenny (either Bicolor or Lawnmower), a smaller butterfly (not sure which yet.. will research) and a smaller Mono (that has been slowly acclimated to full marine conditions and will be moved to a larger tank within 2 years). <<A few comments... The Mono is a true marine fish and always best kept in full-strength marine systems...and yes, will need a bigger tank than you have now. A Butterfly may work out, but a swift and agile Dwarf Angel species may do better as the Toby is likely to get "nippy"... Centropyge loricula gets my vote. And obviously, you are going to need to augment/get better filtration>> I have a few questions. <<Okay>> First, it's about my protein skimmer. There are 2 sizes of wooden air stones. The smaller size fits in the tubing but doesn't produce nearly enough bubbles, while the larger sized produces enough bubbles, but doesn't fit in the tubing, and the air goes up both chambers. I've tried taking out one level of the tubing but it doesn't seem to work that well. My air pump is older but I've checked for any kinks in the tubing and I'm sure it's working fine. It's a large sized pump. Any suggestions to remedy the air-problem? <<This sounds like a result of poor engineering/design re the Berlin skimmer. You could try carving "custom" air stones from Basswood (can be found at most "hobby" stores) to maximize available space, but your time/effort/monies would be better spent upgrading from this less than adequate skimmer. My suggestion for your current setup would be the AquaC Remora or Remora-Pro>> Second, I would like to add a second filter to increase the anticipated filtration needed with the added livestock. <<Indeed>> I have read many articles, and it seems like the Aquaclear 50 or 70 would be preferred over adding a second Whisper 60 filter, but I'm not sure. <<Maybe...but like the Whisper filter it will require diligent care to prevent buildup/decomposition of nitrogenous waste while providing little in the way of biological filtration. I think you would be better served with a fluidized-bed filter as these don't accumulate detritus like the other filters and are able to "ramp up" quickly with changing bio-loads>> I have a smaller tank setup with an Aquaclear, and like the functionality as well as the options for filtration. Should I bother adding another filter? <<I think some additional biological filtration will be needed/have benefit, yes>> If so, should I add the Aquaclear or the Whisper (or any other suggested filter?) <<The fluidized-bed filter...as stated>> Third, if I do add the Aquaclear, should I keep the 3 stages of filtration as is, or would trying "3 stages" of activated carbon work? <<Mmm, yes...if you go with this type filter, carbon and Poly-Filter will serve better than merely "trapping" particulates with a mechanical filter material>> Thank you (all) for the incredible amount of knowledge and information I've gained through this site!!!! Eric <<We're all quite happy to share. Do also consider adding a sump for the additional water volume and space for ancillary equipment...as well as a vegetable refugium with DSB for organics/nitrate removal along with a slew of other benefits. Oh yeah...don't forget to add more water movement in the display...the fish will appreciate it and the system as whole will benefit. Regards, EricR>>

Re: Filtration For 55-Gallon FOWLR - 09/10/07 Eric, <<Eric>> Thank you for the quick response. <<Quite welcome>> I've been around saltwater aquariums for only about 6 months or so, and my roommate (who introduced me to freshwater a year ago) has had freshwater for about 5 years... <<Thank you for this...is always helpful to know the experience level of those I'm trying to assist so I can ascertain the depth of explanation required. And while we're sharing...I set up my first fish-only marine system in 1977...began with freshwater keeping some years before this>> and neither of us have really heard of Fluidized-Bed filters, even though I read WWM about 10 hours per week since the start of my saltwater tank... <<I see...some helpful reading here (http://www.wetwebmedia.com/fluidbedfaqs.htm), as well as here for more general marine filtration (http://www.wetwebmedia.com/marine/setup/filtration/marineFiltr.htm). Do be sure to follow/read among the associated links in blue as well>> So I will definitely read about them in WWM. <<Ah...very good>> In the meantime, can you make some quick suggestions as to a good brand (just like you did with the Skimmer?) <<Mmm, not a lot of choices really...try a keyword search on the NET for QuickSand and/or Rainbow fluidized-bed filters>> And if I get an excellent skimmer such as the ones mentioned below, will I still need to add an additional filter, such as the Fluidized-Bed or Aquaclear/Whisper? <<Maybe not...will depend much on your stocking level and species selection. But the fluidized-bed filter is a "good to have" device for a FOWLR tank that is fairly inexpensive and easy to install...worth doing anyway, in my opinion>> I will definitely purchase more powerheads to increase water movement. <<Excellent...do also read here (http://www.wetwebmedia.com/circmarart.htm)>> I have also been thinking... (a lot about my stocking plan) I figure it's better for the fish - stress, health (and my pocketbook) if I go very slowly and plan out my fish purchases first. <<I am much in agreement>> But about the Centropyge loricula - (actually, I was leaning toward the Lemonpeel angel... as a consideration instead of the butterfly) <<The Lemonpeel is a much more delicate species...definitely not for the novice/for this 55g system>> Let's say I don't purchase the puffer, would the Chaetodon auriga be a more hardy addition than a pygmy angel? <<This is a very good "aquarium suitable" species of butterfly...and I think this would be the better long-term solution for you/your tank over the Toby>> I agree with you about the fin nipping of the puffer, and that's another area for research. <<Indeed>> Further, will the Mono be OK with the puffer? <<Probably...for a time...is very quick>> Do you foresee any issues with the pygmy angel or the butterfly? (He was my first fish, and is in full marine conditions now, but is a bit skittish, and VERY fast). <<Will be okay as far as compatibility I think...but as you already know, the Mono needs a bigger tank>> Thanks again for all the help. Eric <<Happy to assist. Eric Russell>>

R2: Filtration For 55-Gallon FOWLR - 09/12/07 Eric, <<Eric>> Once again, thanks for the help. <<My pleasure>> I've been reading about the fluidized-bed filters and I'm not really sold on it yet. <Oh?>> From what I've been reading, it looks like it's mostly for highly fluctuating bioloads and/or large tanks with heavy bioloads -- mostly in the beginning stages of cycling, correct? <<Mmm...is not just for "the beginning stages." And as for highly fluctuating bioloads...that is why I recommend them as this is a prevalent condition with heavily stocked systems and/or systems with messy feeders...both being very common to FO and FOWLR systems>> Either way, I'll read more. <<Okay>> This is actually a pretty exciting time, as I'm reading and doing a lot of research about fish. <<Excellent>> I've probably seriously thought about a dozen different fish that I'd like to add. <<Do feel free to bounce your choices off me once you get down to your short-list>> I'm not sure yet. <<And no need to rush it>> As for the question about the skimmer, the reading I've done in regard to the skimmers suggests I should ditch the skimmer I currently have and upgrade to a better model. <<Is my opinion as well>> Luckily the skimmer came included with a great deal on a 30 gal tank I currently have set up, so it won't be much of a monetary loss. <<I see>> As for the skimmer, I'm thinking of an AquaC Remora hang on variety. <<Is an excellent choice>> Those are pretty expensive though. Are there sites that I could find those on for cheap? (Besides Ebay, Craigslist, etc.) <<Hmm, not that I am aware...but the couple-hundred dollars spent on a quality skimmer for your system is cheap by comparison>> Thanks again, Eric <<Regards, EricR>>

Fluidized bed: Should I pull it?   8/26/07 Gentlemen, I have a 60gal/80lbs Cured LR/Venturi Skimmer/Fluidized bed/fish only system. Its been up just for a month and a half. I understand from your site, that FBD's tend to build Nitrates. <Possibly... many systems have countervailing influence/s...> 1.Given my qty of live rock should I pull the FBD or its not going to harm me to keep it going? <I'd wait and see here... perhaps the denitrifiers elsewhere will utilize the extra NO3> 2.On a different note, I see black algae growth on the back walls of my tank. <Or, maybe not...> My Turbos and Nerite are not eating them. <Ah, no... is likely unpalatable... a mix of microbes, BGA...> Are there any snails which would munch on them? <Not likely> And once again thanks for all your help! Cheers Gans <Some valuable lessons here... I would be reading re Cyanobacteria on WWM. Bob Fenner>

A question on Fluidized Beds - 07/01/07 Hi Guys, I bought a used 60 gallon recently and it comes with a Sea Storm Fluidized bed filter. Its driven off a separate power head and when active the sand rises to above 1/4th to 1/3rd of the column. <Am familiar with this...> Along with the sand media, there seems to be some small gravel in there which probably crept in there over time. My question is, how do I determine the proper flow rate for the filter? * How high should the sand media rise? Currently its churning but does not go up very high. Stays about 1/3rd of the tube. Is that ok? Or should it rise higher? <No worries, as long as it IS rising... and NOT being pushed all the way to the top, out...> * If it must go higher should I use a more powerful powerhead or get the gravel bits out? Cheers! <I would not change the pump mechanism... is fine as it is. Please read here: http://www.wetwebmedia.com/fluidbedfaqs.htm re FB use. Bob Fenner>

FBF (Fluidized Bed Filter) emptying into sump with DSB (Deep Sand Bed)   9/17/06    Great site lots of info keep up the great work please! My question has to do with using a DSB after a DIY FBF. I've read that you feel a FBF produces a lot of nitrates <Some can/do...> and I was curious as to the use of a DSB in a 150 gallon Rubbermaid sump as a way to process the nitrates. <Can be made to work> I have a 125 gallon FO tank with a 1/2 inch of sand and very little live rock it houses a sohal tang a queen angel and a niger trigger  and a 150 gallon reef tank with 200 lbs of live rock a DSB several soft and stony corals and 5 tangs 2 dwarf angels 2 small damsels a six line wrasse and a neon Dottyback. They are connected by the 150 gallon sump along with a 80 gallon sump and a 30 gallon refugium I process wastes with two 5 foot DIY skimmers and a DIY denitrator and I keep calcium, alk and ph in check with a DIY calcium reactor and a DIY Nilsen reactor. <Great to have the drive, knowledge, skill for such DIY projects> Water changes 10% are done monthly and all parameters are stable. My thoughts were to run the water from the 125 tank through the FBF then into the 150 sump with a DSB, the water from the 150 tank would dump directly into the 150 sump from there it would dump into the 80 gallon sump where the protein skimmers denitrator and calcium reactor are located. the Nilsen reactor is connected to the automatic top-off system. My goal is the best water quality I can possibly produce with the livestock I have your input would be appreciated                              Don <This is the order I also would process your water in... And I also think the addition of the FBF will be "worth" it. Bob Fenner> Fluidizing ChemiPure?   4/28/06 Love the site!   <Glad you enjoy it! We're thrilled to bring it to you! Scott F. here today.> I was interested to know your thoughts on removing Chemi-Pure from the bag and using it in my Phosban Reactor?  The manufacturers do not recommend removing it from the bag, but I cannot see the harm in this situation (if run properly through the reactor, low flow, etc.) Do you foresee any problems in doing this? Regards, Andrew. <Good question, Andrew, and the answer is kind of unclear. While I'm sure that this media would fluidize nicely, I really don't know if there is any advantage to be gained from using the media in this manner. On the other hand, by making sure that the media is thoroughly exposed to the water column, you may be using it more efficiently. My best recommendation is to contact the manufacturer, Boyd Enterprises, and get the answer from them. This is a great product, and if it can be used in this manner, it would that much better! Please let us know what you find! Regards, Scott F.> Sequential fluidized bed reactors in a marine aquarium - 2/28/2006 Bob and crew, <Jery> Great site!  (Although I have probably spent too much time on it!) <Is that possible? I hope not!> Despite having spent significant time on your site and elsewhere, I cannot find an answer to my question.  Recently, I noticed that a waste water facility uses an anaerobic fluidized bed reactor.  (Funny the things one notices when they get into this hobby!)  This may be a silly question, but I know very little about such things.  The idea started me to thinking, which leads to this question. I was wondering the following:  If a person was to run two fluidized bed reactors sequentially, would the second act as a denitrator? <Mmm, depending on flow rate, ambient DO... and digestible nutrient... possibly... to an extent almost all such surfaces present a degree of aerobic/hypoxic/anoxic-anaerobic media effect>   In other words, is the water that comes out of a fluidized bed reactor sufficiently deoxygenated to allow anaerobic denitrifying  bacteria to grow in the second reactor? <At some point, yes> If it does not work, it strikes me that it would be caused by insufficient ammonia or nitrites to consume all the oxygen.  Do you agree or would it have other problems? <Very possibly... I would move the resultant water NOT directly back to a system with biota present, but into a sump, area of extensive baffling... perhaps lit with photosynthetic life present... Do you understand the concern here?> This leads to a counter intuitive thought.  It is more likely to work in heavily stocked or even overstocked aquariums. (Honey, we are going to have to buy a whole lot more fish to keep the water quality up!  Dare to dream...) <Heee and suffer the consequences!> Thanks, A Hopeless Experimenter. <Years, okay decades back I worked on devising a sort of "clam shell" that would enclose a long length of polyvinyl tubing that would have a type of media wound inside it (Ceca-mat), sort of like a "pipe cleaner", with a low flow pump source, trying to acheive the sorts of ends you hint at here... couldn't "dial it in" sufficiently to disallow the "tinkering" with addition of carbon source to feed anaerobic digestion... to make such units applicable/saleable to aquarists (in honesty). Cheers, Bob Fenner> Re: Sequential fluidized bed reactors in a marine aquarium  - 3/1/2006 Bob, <Jer> Thanks for the reply.  I have a follow up question if you would be so kind. <Hotay> I think I understand your concern, but I want to be clear.  Your concern is that the water leaving the second fluidized bed reactor would be so carbon dioxide rich and oxygen poor that it would be dangerous to the biota? <Mostly, yes> Now on to my real questions.  In your reply you told me about your "clam shell" experiment.  Two things puzzled me and I am entirely too curious to let it pass.  First, you mentioned that you had to adjust it entirely too often to make in a reasonable solution. <Yes... flow rate and a ready source/substrate (carbon compounds are what I used, what most folks use) to otherwise feed the autotrophs> I have read that about other types of denitrators on your site.  But I have not read about how one knows how to adjust it.  How do you measure denitrification in real time? <Most such measures involve effects... the presence of nitrate... change in pH, dissolved oxygen...> Do the nitrate levels in the water change that quickly? <Can, yes> Or do you measure the oxygen levels? <Ditto> I have not seen oxygen meters in either online or local fish stores.  If I have to buy an expensive industrial meter, my wife will nix any experiments for sure! Second, you mentioned having to use a carbon source.  I did a search on your site and found a place where you said that sugar was such a source, but I could not find it explained.  What is that all about? <How to put this succinctly... the microbes involved are chemo-autotrophic... do "use" nitrogenous" material/s, but also require other essential nutrients, of which carbon (and/or its chemical family, e.g. S) are often a/the rate-limiting factor... "No carbon, no nitrification"> How is this different from denitrification in a deep sand bed? <Mmm, what is it you mean by "this?"... the processes are the same... some reaction pathways are more favored in one/the other...> Sincerely, Just Enough Knowledge To Be Dangerous <You're ahead of me. Bob Fenner> Re: Sequential fluidized bed reactors in a marine aquarium    3/2/06 Bob, <Jer> I just want to thank you for the great site and kindly answering my emails. If I decide to experiment with this, I will let you know what happens. Jery <Do appreciate this, thank you. Bob Fenner> Overkill? Fluidized Bed filtr. SW  - 02/27/06 Bob, <David> I'm amazed at the amount of data on the WWM site. A big thanks to everyone that is a contributor. <Welcome> I'm a "gadget nerd", and an engineer in the wastewater industry. I've been  a FWA for over 30 years, and finally have some money to burn on a reef setup   (I've got a funny story about doing "revised" budgets - 3 times - on the system I'm working on). Nonetheless, I think/feel that a system can be setup to "take care of itself", inasmuch as possible. I understand that the biological process is not   "steady state", and that there will be fluctuations in the biological loading of the system. This, in turn, impacts the water chemistry, which WWM has done a   wonderful job in explaining, especially the importance of buffering the water. <Simple... there are some folks that have gone "advanced"... Randy Holmes Farley, Craig Bingman, others...> I'm an experimenter, and am playing with a setup. I am putting in an 80 gallon or so system (main tank), plus a 39 gallon refugium, of which I'll   probably get beneficial use of about 25 gallons, or so. I am using a skimmer, directly from the tank (goes to a sump, first), which will have a return to a   baffle/overflow to the refugium. Here, I am going to "split" the flow, by part  of the water going under the "sand" in the refugium, and part flowing directly   into the refugium (this flow will be adjustable, by the use of an  adjustable "flap gate"). I am concerned about flow patterns within this  refugium area, as I want to build a layer at the bottom of this compartment  where I want anaerobic processes to happen. The top of this layer will have some  LR, mangroves, algae, and various critters. These two flow paths can then  either be converged into a single compartment, for return to the tank, OR  one/both can be run through a fluidized bed. The reason I am considering a fluidized bed (FB), is that I am not sure the bed in the refugium will be sufficient.  At low livestock levels (and  minimal feeding), I think the FB may be overkill.  I have also thought of  putting the FB prior to the refugium, and leaving the option to either have it  flow through the refugium, or bypass it altogether.  I do want to slowly  increase my LS levels.   The reason I am considering the FB at all is that my refugium has limited space. It is 36Lx12Dx24tall.  This gives me a smaller surface area for the  sand in it, hence the "increased" SA by use of the FB.  The bacteria levels  will self-adjust, based upon the nutrient loading of the tank (with gradual   changes being the rule-of-thumb). Am I nuts on this? I've read WWM, and haven't found this specific  question. Thanks David P. <Fluidized bed filtration can be very useful in situations of vacillating and high bioloads. You can always subtend or remove it... Bob Fenner> Fluidized Bed Filters 2/28/05 Hey guys, I am setting up a new semi reef tank and I was wondering how I should set it up, filtration wise. The tank is 60 gallons and I am planning on only including about 30 pounds of live rock. I own a Fluval 404, a UV filter, and a Fluidized bed filter. I know you don't like FB but I was wondering if it would work considering the low amount of live rock I am going to use? Thanks, Steve  <If you choose a very high quality, open structured rock, 30 pounds will be plenty for your tank if you keep reasonable stocking levels. In my opinion, a better rule of thumb is to fill 1/3 or so of the tank volume with rock. Rock from the Marshall Islands and Kaelini as well as some other locations provides much more volume per pound. I personally am not a fan of canister filters, UV OR FB's for reef tanks. Most of us don't maintain UV units well enough for them to be effective. Canister filters and fluidized beds encourage nitrate accumulation by optimizing ammonia and nitrite processing AWAY from the live rock where the resulting nitrate can be processed. Fluidized beds are phenomenal for very large bioload systems, but for the average reefer (even with relatively small amounts of live rock) they are probably not helpful. Best Regards. AdamC.> 

Marine Aquarium Plumbing: Dumpbuckets and Sand Filter 1/30/05 Hi. I have spent a day looking over you great site and couldn't find a answer for my question. I am relatively new and plan to a 6' 2' 2' with a 4'1.5' 1.5' sump running off a overflow straight into a fluidized bed <this is a mistake already... raw water with solids will burden your fluidized filter (clog over time) and moreover, you should skim raw water first to remove as many organics as possible before going downstream to bio-filters. This will reduce nitrates... and the burden overall on water quality> ...but my biggest problem that I can think of is that the return is going to be running through two dump buckets and there is going to be water fluctuation and wave's in the main tank so every time a wave goes past the overflow it's going to get a lot water at once and none after. <another mistake my friend... not only will this be untidy (salt creep and low water/exposure), but it will wreak havoc with protein skimmer performance anywhere inline. Dump buckets are a novelty and simply do not scale down to hobbyist sized applications. They are really just practical on public aquarium sized displays> Will the fluidized bed be able to handle it or will I need some sort of buffering device.  Thanks in advance. Glen <look instead at my closed lop manifold suggestion... do a keyword search on our website (Google search tool on the home page) for an article called "goodbye powerheads". Best regards, Anthony> Converting Fluidized Bed filter to Calcium Reactor Hello from Calgary to the Crew << Hello up there, Blundell here this afternoon. >> Your service to the hobby is incredible and you have improved my personal experience greatly.  Thanks in advance.  I have a 66 gal reef setup that is 2 months old that I inherited from a friend, it had been running for 6 months previously.  I have hence nursed most of it back to health.  A Rainbow fluidized bed filter came with it and it has been running the whole two months, from what I have seen on WWM the FBF is not necessary and potentially detrimental now that the live rock seems to be actively developing a health population of coralline algae and life in general.  If I were to replace the sand media in the FBF with media for a Calcium reactor and add the required CO2 system to the input of the FBF could the FBF be converted to a Calcium reactor. << I would search around on the internet for DIY calcium reactor plans.  Most people have used a pvc base to make them.  Your idea could work, but rather than converting the FBF over, it may be easier (and possibly cheaper) to just make one from scratch. That is what I would do. >> Hopefully I am making sense. Thanks Lonnie <<  Blundell  >>

Fluidized Bed Filters Hi guys, I've read your review on the Saltwater Aquariums Dummy's guide and you had mentioned that FDBs are not appropriate for home use.  I understand FDBs are heavily used in commercial applications but little information has been found on hobby usage.  Can you elaborate on why I shouldn't use a FDB on my system. <Other than being almost always a superfluous bit of gear (their only use is for accelerated nitrification) these devices overdrive the forward reactions of nitrogen cycling... they often result in nitrate accumulation> I have a 125g which is going from reef to fish only.  It will have 150lbs live rock and lots of non aggressive fish.  Can you please point out the issue of my filter setup being an FDB and an airstone for oxygenation powered through a UPS. <Mmm, "point out the issue"? You don't need the FDB... try turning it off once your system is established... zero effect. Bob Fenner> Thanks for your time, Jackson

Fluidized Bed Filtration Dear Mr. Fenner, I am setting a 500 gallon(2200 litres) fish only aquarium and want to use a large fluidized sand filter for bio filtration. Why am I told this is risky? <Mmm, perhaps "risky" in that it's ill-advised to use "just" this type of filtration in such a size, type system... In other words, you would be better advised to employ other means; mechanical/physical, perhaps biological and the chance (space) to add chemical means in your design... in addition to the fluidized bed...> and could you please explain what IMHO means? <Oh, an acronym for In My Humble Opinion. Bob Fenner> thanks, George

Fluidized beds Hi, A friend of mine gave me a Sea Storm Fluidized bed that had worked great for him.  <even a blind squirrel finds a nut sometimes> I cleaned the equipment and I used the same power head that he used. When I attached the filter and then started it, the filter pumped well but shot all of the expensive sand that I bought into my sump tank. What can I do to correct this problem. I do not see any ways to adjust the flow rate or stop the sand from coming through. <the cleaning likely improved the pump performance. Go to the local Pet or Hardware store and get a plastic valve or adjustable clamp for your tubing to adjust the PH flow> Thanks, Brion Pechin <best regards, Anthony>

Fluidized Sand vs. Trickle Filter In the "planning stage" for a 200 gal. F/O saltwater system. Will have protein skimmer but requesting comments re: Fluidized sand bed instead of a typical wet/dry trickle filter. Thanks, Skipper30217 <My preference of the two would be for the W/D. Fluidized bed sand filters rob your tank's water of oxygen and can get very funky if you lose power. -Steven Pro>

Fluidized filter I am using a fluidized-sand filter for my seahorses tank. My question is, in the event of a power outage how long will the nitrifying bacteria remain intact.....................Thanks, Lou <Minutes... depending on temperature, the units make-up... a few to several. Bob Fenner>

Die off problems IV Hello again, I am pondering removing my fluidized bed filter but am wondering what sort of biological filtration I could use in its place? I have ordered another 30lbs of live rock as you suggested. <With the additional liverock you should have plenty of biological filtration.> In my previous freshwater tanks there was no biological filter that I was aware of. Can the crushed coral substrate and the live rock serve as a biological filter or do I need something else? <Liverock will work fine.> Any input and advice you could provide would be greatly appreciated. The main reason I am considering this is because I am having another large algae bloom and I am wondering if this is due to the bed filter reseeding itself after I have added new sand. <Usually due to nutrients.> Also I want to increase the water flow to the tank which seems suppressed due to the resistance from the bed filter at the end of the filtration line. <Yes, these filters greatly reduce flow and increasing circulation would be a good idea. -Steven Pro> Jameel

Power Outage Bob, There was a power outage in my area last night. The good news is the power was only out for about an hour. The bad news is that I fell asleep prior to the power coming back on and the outage tripped the GFI's in my tank, so the tank power was out for about 6 hours. My first question is does anyone make GFI's that don't trip when there's a power outage. <As far as I'm aware they can/do trip or not depending on the "even-ness" of electron flow through their circuits... not whether the power is on or not... Perhaps moisture from condensation had something to do here with yours tripping> I know I need GFI's because I don't want to get zapped, but now I'm going to be worried sick every time I go on an overnight trip that the power will go out and the tank power will be down until I return to reset the GFI's. <Practice throwing the breakers over (on/off) on the circuits that are GFI protected in your house... they shouldn't trip... they do sometimes, "go bad"... may need to replace an in-line one... or have help locating the leg/s that are allowing the fault> My second question concerns my fluidized bed filter. When I first started setting my tank up last summer, I had originally planned on an all fish tank so I installed a fluidized bed filter on the sump. Instead, I've ended up with a flow blown reef tank (live rock, skimmer, many soft and stony corals and only 2 small fish). I've been considering shutting down the fluidized bed filter for some time now,  <Yes, I would... just pull it> but since all water parameters were excellent, I figured why mess with a good thing. <May not be as "good a thing" as you can have> Well, I've read that the bacteria in fluidized bed filters can die very quickly if there is no flow through the bed (like I had for six hours last night!) <An hour is too long...> Well, I didn't want to blow all that dead stuff into my tank, so this morning when I restarted everything, I mad the decision to shut down the fluidized be filter. Do you think this was wise, or should I turn it back on.  <You were wise, and fortunate to have done so> Sorry this was so long winded. By the way, the good news is that everything seemed to be doing fine this morning when I left for work...hopefully all will be well when I return this evening. <Yes> Thanks for you help, Phil in San Diego <Bob F. in San Diego... where in our area we didn't have an outage... that dang futility, I mean utility!>

Re: Aquariums and Filters Thanks. Yes, I am interested only in freshwater (for now anyway). How about fluidized bed filters? I know nothing about them, but read that they are supposed to be the best biological filters for the money. <Only where such "rapid response" systems are called for... i.e. in high, fluctuating bio-loads. Otherwise largely unnecessary... and in some cases, more source of troubles than they're worth> As another alternative, I was thinking about the possibility of Marineland's wet/dry filter, the Tide Pool I or II. The Tide Pool I is supposed to be good up to 80 gals. Any thoughts? <Nice units. Amongst their best products. Bob Fenner>

Bob, What is your opinion on fluidized beds? >> Very useful nitrification devices for facilities with large, and varying bioloads... like fish hatcheries, wholesale facilities... Generally unnecessary in any hobbyist set-up... often guilty of overpowering the forward reactions of ammonia conversion. Bob Fenner

Bob, I appreciate the quick reply thank you very much. I was wondering if you could take time to answer one more question for me. I usually don't use biological filters on my reef tanks (besides lots live rock and live sand) but this tank will have a high bio load so do think I should stick with the fluidized bed or just use the live rock as a bio filter. Oh ya one more thing compliments on your book purchased yesterday and it was well worth the money!!!!! Thanks Bob <Thank you for the kind words of encouragement. If I had a fluidized bed filter laying about (I do...) I would hang it on to the system for if/when there might well be biological filter-needing anomalies (which we do have), like big additions, removals of live rock... otherwise, as you hint, the rock and sand are more than sufficient for boosting nitrification. Bob Fenner>

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