Plenum or DSB/Backup Power – 06/30/07
Hello crew.
<<Howdy Eric…EricR here>>
I'm in the midst of planning a 125g mixed reef setup and have a question about whether or not to employ a plenum layer.
<<Okay>>
If I were to have an Aragonite sand bed of <1", would I be good (in terms of keeping nitrates to a minimum) with not using the plenum?
<<Hmm, have you read any of Bob Goeman’s writings on plenum methodology (here’s a place to start: http://www.saltcorner.com/sections/guest/goemansandgamble/sandbedspart1.htm)? Whether going with a DSB or a plenum system, a sub-1” sand bed is going to do little for “direct” Nitrate reduction>>
I am planning to use a 30g sump, and if I were to go the DSB route there, would I use a plenum layer??
<<Is up to you…I prefer simply to go the DSB route>>
Oh, and I have one more question regarding backup power--aside from something like a generator or a Yugo battery, are there other more convenient options for a tank of this size that you'd recommend?
<<There “are” battery-backup systems available…most designed as backup computer power. I find these expensive and of limited utility re hobby use…though admittedly I have not done any extensive research on what is available. For a system your size, a small gas-powered generator to run the “essentials” would likely cost about as much (or less?) than some of the proprietary battery-backup systems and will provide much more useable and sustained power…in my humble opinion, of course>>
Thanks for the education and terrific website! Eric
<<We’re pleased you find it of use. Eric Russell>>

Re: Gamble/Goemans book review
Hi Bob,
Thanks for sending me a copy of this letter. Let me first say the issue here was taken under consideration early in the process of trying to understand why plenum systems appeared to function better than deep sandbeds directly on the aquarium bottom. This was probably about 1998 when the information coming from numerous resources began to mount. At this point much of any reasonable data was being ran through Dr. Craig Jones, a brilliant scientist who had been a CIA biochemist and was now a consultant for NASA, various other government agencies and major food, computer and oil companies. A very quiet individual who preferred to stay out of the limelight and work in the background, which suited those he consulted for! Anyway, when the evidence became clear how plenum systems differed, a decision was made by Sam and I to write a book. And, plenums were at that time getting a badmouthing by some people who simply did not understand bio-geochemical pathways and preferred to use what sounded like logic to promote their agenda.
I should also add that during the preceding couple of years Sam and Dr. Jones accomplished many interesting experiments that added weight to the growing pile of research information. It was time for disseminating the
'pile' of information we had assembled. And, some of that is still proprietary, yet a new device called ECO-Aqualizer is touching on some of the results shown in our previous research efforts!
Honestly, the assortment of data from previously research books and our own data melted into a vast 'ocean' of stuff ­ which consisted of hundreds and hundreds of pages of subject matter that I was desperately trying to
formulate into a roadmap that would serve as the book's index. Keep in mind I did the whole writing effort and anyone wishing to place blame for that can blame me.
Since Sam was the scientist and I was the 'writer' it fell upon my shoulders to take the scientific data and put it into a format that could reach the broadest possible audience, which I estimated to be about 80 ­ 90% of hobbyists. And because of that it was time to decide just how reference material should be handled before the actual writing began. I estimated the majority of science related material would fall into two or three chapters. Styles were considered on how to properly present the reference material. I asked Sam his thoughts on this situation and he suggested contacting Melinda Kramer, who has a Ph.D. in the English language and has written 'many' books on the subject for Prentice Hall Publishers. Actually, she is Sam's sister! In fact, she was on her 14th edition if memory serves me correctly of 'Prentice Hall Handbook for Writers' when she was contacted. There could not be a more knowledgeable or well-known individual for discussing this matter!
When it became evident those technical chapters would have many, many references per page, sometimes mid sentence, (and some might simply be guesswork as to where they belong because so much water had passed under the bridge so to speak when writing time arrived) we all came to a conclusion that we would lose the broader audience if a mumble-jumble of references were presented. That concerned us because it was just that audience we were aiming at! The decision to go the road we did came only after much sole searching and we realized we would not make some of the more scientific minded and/or more technical writers happy with the layout of our work. But, we thought it the best way to go to reach the masses. Martin Moe and Dr. Jaubert also stated the concerns, as did your reader. Both came away understanding and respecting our decision.
As for publishing concerns, I contacted almost all known publishers with copies of our manuscript. Most said thank you but no thank you, as the subject matter either did not fit their present line or there was not 1000
color photos. One 'major' company called me and their president said the info presented in the book was fascinating, but the corporate board felt it would harm their aquarium product division!
After a year of searching for a publisher I turned to self-publishing and the CD format was the only reasonable and economic approach we could take. Since Sam Gamble's company is named 'Keys Mariculture' and he made the meat of the book possible, I used his company name as the publisher and produced what we thought an innovative business card sized CD. After getting excellent reviews by Martin and Dr. Jaubert, who both thought it necessary to spread the content of the book, they gave us permission to publicly quote them. After their quotes became known, Marc Weiss contacted us and wanted to distribute a full size CD version. You could say the word was out and the book was of true value and Marc decided to capitalize on it! Of course with his ability to distribute worldwide, we agreed to his terms and what transpired came about without much input from us as time was of the essence where Marc was concerned. Anyway, it allowed both Sam and I to put more time on other projects, something that was lacking because of our involvement in searching for ways to sell the book.
<I understand this!>
Will there be a paper version is a good question. If we can find someone wanting to publish said version, Sam and I would be happy to construct that version with updated info and in a more acceptable format. But the price would have to be right because as of now we have lost much money on this whole endeavor. But honestly, making money was never a factor, it was our passion for understanding the microbial processes which are the true foundation of every aquarium that drove the whole effort.
We realize the writing approach lacks certain more acceptable approaches in style, but at the time we made the decision, we thought it the right way to present a more readable text for 'average' readers. In hindsight, maybe
that was wrong, but Martin and Jean thought we still did a commendable job. I hope this helps.
(What can you tell me about the reader questioning our book.)
<David (Dowless) is a friend, cohort that helps on our site WetWebMedia.com>
A safe and happy New Year to you and family, Bob
<Thank you Bob. To you and yours as well. Bob Fenner>

Sump <plenum>
Hi there, my first question is what is a plenum when referring to a sump? I hear the word but don't know what it is. Next I'm planning a 120g f/o tank and my sump is a 65g tank I have laying around. I was going to make 3 separate compartments, first for skimmer second was for live sand and live rock and third for return pump and heater. Now the question is if I want to keep macro alga in sump can I just buy some and put in the compartment with live rock or do I need another section for it? Last question, will a 65wt power compact be sufficient for sump or should I go higher.<depends on how close the bulb is to the sump.> Ok, one more do you favor 24hr sump lighting or 12hr after main tank is out? Thanks again, love your site. Josh
<A plenum is a dead space below your substrate used for nitrate reduction. Many a man/woman have failed due to improper set up of their plenum. If you want to go with the plenum I would search out some instructions from Dr. Jaubert. I would go with a Deep sand bed instead of the plenum.
You could put the sand rock and algae all in the same compartment. If the flow rate is too fast the algae may not be effective and it would be a better idea to put the algae in a separate compartment with less flow. Both 24hr and 12hr lighting have their benefits depending upon what types of life you are keeping. Check out our info on Algal filtration. -Gage
http://wetwebmedia.com/algfiltf.htm> 

To Plenum or Not, Filtration woes....
Good Sirs,
<Where?>
I am sorry for asking so many questions but I truly don't much trust the LFS guys and I don't want to cause any harm through my own idiocy if I can avoid it.
<Yeah, my buddy at the LFS is always trying to sell me stuff, it is hard to trust a salesman.>
I am still in the planning stages for a 90Gal Reef. To start I plan on a 4"+ DSB and plenty of live rock -- at least 100pds. to start and 50pds. of base to be seeded.
Also from my understanding the live rock will seed the sand over time ... but would it be worth investing in 25 pd.s. or so of live sand to "seed" the 200 pd.s of dry sand with?
<Up to you, it is going to cycle sooner or later, maybe you have friends with reefs who would not mind sharing a few handfuls?>
Also, should the DSB have a plenum? I've read so many conflicting theories in this area. What is your experience?
<I would go with one or the other preferable the DSB, IMO>
Now, the second question/problem... I custom made my own stand (beautiful deep red oak) but at the time I hadn't been thinking of using a refugium so I only have about 9" between my uprights (the internal frame is 2x4). While this stand could EASILY support an elephant, there isn't much room to fit a refugium/sump inside of it. so....
<yeah, math, numbers, visualizing things, not my department.  I have to do things a few times to understand, bub, need to get the tape measure.  Yurp, 9in is not very big, so there is no way to wiggle a tank/sump behind the stand?>
To keep everything happy, besides the live DSB and rock I obviously need a skimmer and a good mechanical filter. For skimming I have ordered a Remora Pro with a pre-filter which leaves me handling particulates and mechanical filtration. Here I am at a loss....
I had thought of using a couple of Aqua-clear 500s with one stuffed with a couple of sponges (rinsed daily) and filling the other unit with sponge/carbon. I like the hi-flow rate these units have (for mechanical filtration only) and thought they might do a good job keeping the system clean. However, they seem to totally get bagged on so I have also looked at the Eheim Professional II Canister. The problem I see with Eheim as a Mechanical Filter would be the necessity of cracking it open every day or two to clean out the pads. Do you see my confusion? Everyone says the Eheim is better but would it be truly better than the above scenario... assuming the Aqua's sponges got cleaned everyday? Could you PLEASE make a recommendation for a mechanical filter?
<I would go with the Eheim, and clean it frequently, but if that is not going to happen then go with what works for you.  I would still try to find a way to squeeze a sump in somewhere, plastic tubs come in many shapes and sizes.>
Also, does this setup (with good mech. filtration) sound decent and viable long-term?
Planned Setup:
90 Gal
4 - 48" VHO (2 URI Actinic, 2 URI 10K)
4 DSB"
100 pd.s. Live Rock
50 pd.s. Base Rock
Remora Pro Skimmer w/filter box (Mag3 pump)
Mechanical Filtration??????
As always the WWM Crew is the best source I know of for the know-how to do it right! Thanks Guys!
<I think once you get everything going you may find that you want a more robust skimmer, the Remoras are great, but on a 90gal I would go with a good in sump model.  Which brings me to my next point; IMO if you can find some way to utilize a sump, modify the stand or maybe put it in a different room and run some pvc you will be better off in the long run.  We have a lot of FAQs on sumps and plumbing marine systems, check them out for some ideas.  Best Regards, Gage
http://wetwebmedia.com/pbfaqsmar.htm >

Reef Lighting and Plenums 3/14/03
Hello Anthony. I am new to Saltwater Reefs and just beginning to explore your WetWebMedia site, which I am enjoying and find quite helpful.
<Excellent to hear, my friend... there is so much to learn/read there>
In reviewing some of the lighting FAQ's I see your point on knowing what you plan to keep in the tank, prior to selecting lighting.
<Quite correct... although we still can make some fair generalizations as per the lighting article posted there>
I am buying a 120G All-glass (48x24x24)tank and have made my live rock which continues to leach for the next month and half.
<Be sure to clean use your protein skimmer very aggressively during this period especially>
I am planning on buying the lighting and given the costs would like to make a good choice.
I am not sure of the types of inverts I want to keep.
My wife and I are long time scuba divers and have kept freshwater fish for many years. We always wanted a salt tank and having retired 2 years ago I now have the time to move into salt.
<No worries... however strict some can be... all can be easy and low maintenance with your continued patience and good planning>
Although I am a few months away from buying our first inverts I was hoping you might provide a more detailed list of your coral/creature suggestions which in your experience would provide visual enjoyment, educational interest and good odds of providing a good life sustaining environment.
<let me suggest then that you stay with colorful soft corals. Nice polyp extension, hardy, tolerant to aggression and damage/propagation, etc. Avoid any stony corals for at least one year (SPS or LPS)>
Based on some of your writings I am leaning toward Mid to high lighting in this size tank and looking at a 4-96W PC from http://www.ahsupply.com/96watt.htm. (Your counsel would be appreciated).
<I'm a staunch fan of metal halide for its overall value instead. Lamp life, trueness of color over time, penetration of water at depth, etc). Still... PCs work very well for corals... just expensive to replace lamps every 6-10 months for corals (years for halides). And the argument that MHs are more expensive to run is complete bunk. "Watts is Watts" and if you add enough PCs to match MH in intensity, you will use more power.>
Possibly growing it slowly to a 6x96W PC if/as necessary. My current plan is to build my reef on a plenum ( http://garf.org/bulletproofreef/plenum.asp ) with 1"-2" sand with around 130lbs of my live rock(http://garf.org/class.html#mold ). Then seeding the rock and sand with live material like GARF Grunge, for curing over the next 3 months under two of the 96W PC blue lights. After 3 months I would add two 96W white lights and turn on the sump and a protein skimmer and begin to add a few fish and corals with the intent to add more inverts slowly over the next 3-4 months. Then to stop and work with the tank as is, building our experience and familiarity with maintenance. Take a check point at 9 month to a year and then start to propagate our corals and add to the tank as appropriate. Are plenums a good idea? When would they not be good to use?
<I don't think they help or hurt much... I personally would not bother installing one. I would recommend deeper sand though (over 3")>
If used should one expect they will need to be taken down and cleaned? If so, how often?
<not necessary if the sand is deep enough or if you stir it regularly (for shallow beds 1-3")>
Your response and guidance would be much appreciated.
Many thanks.
<kind regards, Anthony>

Monaco-style aquarium setup - 6/27/03
Hi! In the book 'Natural Reef Aquariums' by John Tullock <Very familiar with this book. I highly recommend it to all reefers and fishkeepers> a pretty good description and explanation of the Monaco-Style denitrification system; An underwater gravel filter plate, covered with screening, sand then another screening, aragonite, coral, LS and LR, etc. as any normal Berlin Reef Aquarium. Does WWM have any experience or comment on this technique of denitrifying? I am thinking about using it in a 75g reef tank. <I don't personally have a lot of experience with this style/method of tank denitrification although, I can see the science behind the set-up. I personally don't think all the layering and filter plate are necessary any longer. Much is known about the deep sand bed and more is being scientifically discovered as time goes on. I believe Rob Toonen is doing some experimentation and I would expect a report in a year or two. Live Rock is your major biological filtration system and add a sump to that and......well..........a beautiful natural reef system. Do use the google search tool on our site and plug-in "Monaco-style". See what comes up. Again, nothing wrong with this technique, but there is a more simple approach (less expensive also) that will do the same with a little less work. Do read through the articles and FAQs on our site about various setups and filtration methods. Have fun! Paul>
Gene L. Louthan

Plenum construction in sump
09/04/03
Dear WWM crew,
I recently constructed a plenum hastily in my sump to battle the persistent high nitrates. the problem is I didn't do it the right way by adding another screen layer on top of the 1st layer and top it off with sugar fine sand. I merely added about 3 inches of coral sand over the egg crate and screen. Is the setup workable to cultivate denitrifying bacteria considering the fact that there's no burrowing critters in my sump as it's empty?
Cheers,
<Well, I think lighting it and grow Chaetomorpha would be a better way to remove nitrates. You can use a Lights of America Security Light as your light source. They're fairly inexpensive, and the right spectrum, not to mention wattage. Mine was $30, for 64watts  of 6500K light. You don't really need the plenum, but the sandbed would be better in your tank. www.wetwebmedia.com/deepsandbeds.htm Have a nice evening, PF>

Doing It The Right Way! (Planning A New System w/DSB)
G'day Bob, Scott and the rest of the wondrous wet web wizards of the watery depths! This is Rob here from Down Under.
<Hey there, Rob! Glad to hear from you again! Scott F. with you again tonight!>
I e-mailed you guys a few weeks back looking for advice on my plans for my FIRST marine tank setup. Scott was kind enough to reply and let me know that I was basically on the right track. He then suggested I go back and do MORE RESEARCH!!!!!!! And perhaps revise my plans. I have. I also have many new questions, queries and doubts!
<Oh, man- I sent another fellow hobbyist back to the books! Part of the fun, though! >
So, here goes..... I am planning on adopting the following species: 1 DWARF lionfish (max5"), 2 LARGE tomato clowns and 1 bubble tip anemone as a start, I'll take my time with these introducing the lion first, then the clowns and eventually if all goes well the bubble tip.
<Glad you're "easing" into the anemone...No need to rush>
All are available (reasonably) locally and all are caught with nets by people I know well.
<Outstanding!>
Current plans are for a 150 gal (570litre) tank 48"L X 36"W X 20"H nice and wide, good surface area (see I do read your articles!) I will also be using an under tank sump of 56gal (215litres) I am really hooked on the idea of natural filtration so this tank will get about 200lb's (90kgs) of live rock.
<Terrific! It will be a very stable system!>
Skimming will be by a locally made (Aussie, Aussie, Ausiie OY, OY, OY) venturi unit running from the sump and powered by a 650 g/h (2500lph) pump. These units are made by a bloke in Western Australia who started building his own DIY setups years ago. They have a brilliant reputation and are much, much cheaper than the units imported from your neck of the woods.
< Awesome- DO support your "local talent" whenever possible! A good skimmer is such an important investment- well worth it!>
Heating will be from 2 - 300W quality units. Lighting will be by fluoro's,  160W of HO and 80W of Actinic (still some doubts as to whether this is sufficient, especially with the anemone in mind.....Your views?).
<May not be enough...Even though your tank is relatively shallow, you might want to add a couple more tubes...You simply cannot have "too much" light for anemones, in most cases...>
All fluoros are very well reflected and powered by remote, electronic ballasts and will be housed in a custom made (by me!) hood.
<The best kind, IMO!>
Circulation will provided mainly from a closed loop running on the inside top of the tank with various injectors placed at strategic locations and depths. This will be powered by the 1050g/h(4000l/h) return pump from the sump. I will have to run some test's to see if this is sufficient, if not extra powerheads will be employed.
<Sounds nice. If you intend to keep SPS or other high-current loving corals at some later time, you may want to consider a pump or pumps that can push 10-20 tank volumes an hour through the system...Like lighting- you can rarely have too much circulation>
O.K. I hear you thinking, this guy's got it together!
<Yep! Very much so!>
Well that's what I thought too! Until I walked into my LFS (600kms away!).
<I've heard of "walkabouts" before- but 600kms...? You're seriously dedicated! I'll never complain about the 20 minute drives to good LFS in my area!>
You see, I had initially intended to use a wet/dry filter in my sump to back up the live rock and skimmer. However on looking closely at the shops fish and invert display tank (120gal) all they had was lots of rock and a protein skimmer! Nothing else! This was a good looking tank with all inhabitants looking bright, cheerful and full of life. I was stunned and intrigued. On talking to the shop crew (Seth and Kath, they make a good team!) they told me that the secret was all in the substrate. Sure enough there it was, 5-6" of good looking fine coral sand with plenty of activity going on.
<A deep sand bed certainly serves as an excellent nitrate reducing "filter"...a nice thing to have>
Anyway I checked it out on the web and found out all about plenum bed construction, Jaubert's method, anoxic bacteria and 0 nitrate levels. After much research I am planning on this stage of using a deep substrate level (5") in my main tank and constructing a plenum system in the sump. The main reason for not using a plenum in both is that I want to aquascape the main tank to resemble a section of reef I know well from diving and having to minimize the rock's 'footprint' would be difficult. I really need your advise on this! Is the full biological filtration method just a pipe dream and is it beyond a beginner like myself?
<No- it isn't! Embracing natural methods is probably the most simple and effective thing you can do as a beginner, or as an advanced hobbyist! Your idea of using a plenum in the sump is certainly workable. I personally prefer "static" ("plenum-less") deep sand beds, as they seem to work as well as plenum-equipped systems (although there is plenty of debate on this topic among hobbyists). If you are going to go the plenum route, it's absolutely vital that you follow the "standardized" recommendations concerning sand bed composition, depth, plenum height, etc. These configurations were arrived at after enormous amounts of testing by researchers like Jaubert, Goemans, Gamble, etc., and are not just random numbers. Most of the people who claim that plenums don't work are the ones who "modify" the parameters of their plenum. You may want to check out Plenum guru Bob Goemans http://www. saltcorner.com site for a lot of good information on plenums...>
I am aiming eventually to 'get into' corals so the idea of continuing the biological filtration cycle with the break down of NO3 to NO2 to NO and eventually to pure N is highly desirable. I await your advice with baited breath oh wise and all knowing denizens of the deep! Sorry this is so long winded, got carried away, as usual, if I mention the word "fish tank" one more time I might find myself without a house keeper, bed warmer and long suffering friend! Thanks for your help guys and gals!  Rob
<Ahh Rob- I think that you're doing great! It's so cool that you're doing the "modifications" and "tweaking" to your system before the system is actually set up! The time that you take now to research the various concepts will repay you many times over with a successful tank! I think a well constructed sand bed (with or without plenum), protein skimmer, and sump, fortified with aggressive maintenance procedures (water changes, etc.) will greatly enhance your chances of success. Keep in touch, and best of luck to you! Regards, Scott F.>  

Mainly marine sandbeds
Just bought Anthony and Bob's Reef Invertebrates book while traveling in Michigan. Got it from Preuss's Animal House...Rick Preuss says its a great book...He should know...his name is in the credits :)
<Ahhh... Rick is a great guy, and truly a lifetime industry friend. He's done much good for the pet fish biz>
....It is a great book though.. and here I always thought that John Tullock was the only one worth looking at...Great Job!!!!
<Wow... that's one heck of a compliment. Not taken lightly by me either. Thanks kindly. I think John's "Reef Tank Owners Manual" is so underrated as having changed the face of the hobby in the early days>   
Question is - I'm setting up a 125 reef to replace my outgrown 55 reef tank. I bought a bunch of Southdown sand to use for the substrate and have found it to be very fine grain (power heads blow it into little sand dunes).
<Hmmm.. the problem is not the sand, but rather the powerheads. I often go into rants about how much I hate powerheads. I'll spare you here and ask you instead to look up my article here on wetwebmedia.com about "closed loop manifold">
I have always used a plenum before but wanted to do just a DSB on this tank.
<Frankly... I have experimented for years with and without plenums and chatted with many others, consensus IMO is that they are useless in private aquarium sized systems. They neither help nor hurt... don't bother>
If I go with the original plan of 3 to 4 inches of sand....Is this too deep for such a fine sand?
<actually... its barely deep enough to even work as a DSB. Do read the chapter in our book you mention above regarding live sand and DSBs... explains all in detail>
Will it pack down like concrete or get gas bubbles? How deep should I go?
<5-6" minimum without a plenum is my recommendation here>
Also ..This stuff is VERY milky...is this milk the same stuff they sell at the LFS called Arag-milk?
<all the same, yes>
Is it any good for anything like a buffer solution?
<yes... excellent, and the reason why it should not be rinsed. Just wet it in advance to dampen/saturate it... put it in an empty tank... fill slowly... distribute water flow effectively, and never worry abut a milky tank :)>
Thanks and the worst part of your book is the fact that I will eventually finish it :) . Thanks, Brian
<be chatting soon... and have another volume of that book series later this year for you! Anthony>

DSB vs. Plenum (1/14/2004)
Steve (or whichever highly-appreciated crew member is answering today), <me again>
Thank you for the response.  To follow-up on a few of your questions/comments...   
<Why put a plenum in your refugium? A simple DSB should work fine.>:  I have read many postings on this trying to determine the best approach.  GARF.org swears by the use of plenums on all of their "bulletproof" systems. <IMO, no system is fully "bulletproof" either literally or figuratively. Some are surely less likely to fail than others, though. The real key is good maintenance habits.> Even in one of the WetWebMedia postings where someone asked the question "Should I use a DSB or a plenum in my sump/refugium?", the answer was "Why not have the benefits of both?  You can include a DSB over a plenum..." <True> I have read having a plenum can be disastrous but it seems that this happens when a plenum is poorly designed/maintained. <Agreed. Anything can be disastrous if mismanaged.> Of course I want to use what is the best NNR method but I have not found agreement on this. <And you will not find it. Put 3 aquarists in a room and you'll get at least 2 differing opinions.> Do you foresee problems with using a plenum or advantages of a DSB rather than a DSB over a plenum? <I think you can do fine with any of these. The key is for you to be willing/able to keep up proper maintenance. You should consider getting Bob & Anthony's "Reef Invertebrates" book and reading the DSB/Refugium/Algae chapters. Very helpful. The rest of the book is great too. You may also want to read some of Bob Goemans writings on the subject.>
<Can you make the refugium any bigger?>:  I might be able to make the refugium slightly bigger but it needs to it inside my stand and I would like to maintain *some* room inside the stand to store food, chemicals, etc.  I also already have a spare 20 gal high aquarium, so this is just a convenient fit.  Are you concerned that a 20 gal refugium will have little beneficial effect on a 180 gal aquarium? <Bigger is always better, but 20G is sure to be valuable. Convenient fit is very important.>
Regarding the 100-150 gph flow rate, I should have mentioned that this is the pump's rating.  The refugium will be located about 1 - 1 ½ feet above my sump so the actual flow rate will be reduced.  I do want the flow to be low enough to give the refugium time to react with the water so, I will be restricting this flow if it appears to be too high.  I had read that a flow rate of 3-10 times the refugium volume is recommended.  Do you agree with this? <Yes, but not so much as to disturb the sand bed. I like to be on the lower end myself. 10X flow in a 20G will likely be too turbulent for the sand and the 'pods>

Jaubert's method
thanks for the reply...
One last Q: what are your thoughts on the Jaubert method...
<Have read about this method but personally have never tried this..
I did get some info for you Dr. Jaubert's method is even more 'natural' than the Berlin method since it doesn't use a protein skimmer but instead relies on a deep plenum in the substrate with low oxygen levels to carry out the de-nitrification process. As described in the Fall 1993 and Summer 1994 issue of  Aquarium Systems publication of SeaScope, to implement the Jaubert method place a grid 1 inch above the bottom of the aquarium with a 1 mm mesh screen on top. Above this place 2 inches of coarse calcareous gravel, followed by another screen and two more inches of sand on top of that. Pile live rock in walls rather than pyramids to leave as much of the bottom sand exposed as possible to perform the water filtration. What happens is that water in the lower levels has been depleted of oxygen so the de-nitrification along with bacterial reduction of other dissolved organics takes place there. Unlike the Berlin method, this process will not deplete trace elements. So additions of trace elements is reduced or removed. It was stated that Dr. Jaubert did 5% water changes per month on his systems.  It should be noted that all of these systems it is beneficial to use "live sand" to introduce the bacteria, worms, and other filtering organisms found in natural ocean systems.  (http://www.exotictropicals.com/encyclo/reef/information/reef.htm), Good luck, IanB>

80 gal. reef tank
I am setting up my first reef tank and have been advised by an aquarium store owner to not use the plenum style system. He suggests live rock with only 1/4 to 1/3 inch of live sand. What do you think?.......Thanks ........Robert
>>
Plenums, and natural nitrate reduction systems in general, can be a real source of trouble... or joy... depending mostly on issues of hobbyists control: proper set-up and maintenance. I encourage you to keep studying and discussing the possibility with other aquarists... and to try a plenum, perhaps in a separate sump (my favorite approach) as they are easier by far in this setting to manipulate.
Bob Fenner

Quick Question - 08/11/2005
Would it be worth my time to convert my sump to a Jaubert system?
<Depends. How much is your time worth?  (grin)  Personally, I am not a fan of the Jaubert-plenum system.  I prefer to recommend a deep sand bed method.  See here for more:  
http://www.wetwebmedia.com/deepsandbeds.htm  and here for more on plenums:  http://www.wetwebmedia.com/Plenums.htm .  Be sure to make use of the links, in blue, at the tops of those pages.  Wishing you well,  -Sabrina>

Nano and Plenums   3/25/06
First off, thanks for the wonderful resources this site provides and the job you guys are doing.
<Welcome>
I'm currently downgrading a 40 gallon FOWLR into a 20L Reef system.  I am considering setting up a plenum system to achieve natural denitrification.
<Mmm, these have largely fallen out of favor... more likely problematical in small/er volumes>
My thoughts are to use 1.5" of crushed coral on the bottom with 1.5" of livesand on the top. I was using a DSB in my 40, but I have an Orange Spot Goby (*Amblyeleotris guttata) *that likes to dig down to the bottom and it seems because of that, I get limited areas for denitrification.
<Yes, likely so. If you go this route, with two different substrates, I'd add a layer of "screen door" (non-metal of course), twixt them>
I plan on running a Sea Clear 150 Skimmer on the system, and filtration will consist
of a magnum 350 with the return water passing through a Laguna 1000 8W UV Sterilizer.
Water movement will be 2 powerheads and spray bar return from the canister filter. I have plans to add a small dump bucket system down the line for surge. Tank will have 1.5 Gallon Refugium lit 24 hours a day with a Coralife 10W 50/50 Bulb. Tank lighting will be 2X 65W PC (110 Total Watts). Tank will have 30 LBS of mature Fiji Rock elevated on slate platforms above the substrate. Livestock load is light consisting of 1 Orange Goby, 1 Cinnamon Clown and 1 Neon Velvet Damsel
<I hope these Pomacentrids get along>
with no plans to add any other fish. Corals added will more than likely consist primarily of Zooanthids, Ricordea,
Mushrooms and Xenia. Base Maintenance will be 20% changes every two days, and top off daily with mix of RO and Tap water.
<Sounds do-able>
Now, that being said, with the equipment being used and good husbandry, will the Plenum system be overkill or take up so much space in the small volume as to useless?.
<Only experience can/will tell>
Would I be better served running 2-3" of substrate and perhaps a Flame Scallop or Clam with lower lighting requirement to
filter the water instead of relying on denitrification.
<Mmm, no to these choices/alternatives>
I am also considering adding a small BTA for the clownfish separate from the corals.
<Mmm, no>
Will the 5-6 W of  light per gallon (assuming some displacement of total water volume due to rock and sand) be sufficient to support a BTA in the long term?  Any advice you guys can provide would certainly be appreciated.
<I would not add, mix an anemone with the other cnidarians in such a system... size, type. Bob Fenner>

A Plenum System? - 04/28/06
I have had a 90 gallon salt setup with an Eheim canister filter running for several years.  I'm taking the plunge on converting this system to a sump system with a refugium.
<<Ahh, great!  Though the canister filter still has some utility to be used with chemical media>>
The aquarium service that I have drilling the holes and custom making my sump has been very good at providing suggestions and opinions/advice.
<<Excellent to hear>>
One piece of advice they had for me was...  when setting up my tank, cutting a piece of egg-crate to form the initial layer on the bottom of my tank.
<<Not necessary...in my opinion>>
They then told me to put a screen over top of the egg-crate, adjust my live rock the way I wanted it, and then to fill the bottom with live sand 2-3" in depth.  The guy I was talking too had said that having that layer of aeration underneath my sand bed would have incredible benefits to my tank.  Do you know what he is referring to?
<<Mmm, sounds like they are trying to tell you to install a "plenum" system...though this is not "quite" the correct method of installation...do a Google search re "aquarium plenum system">>
Is this fact?  Fiction?
<<Some debate here, but I feel a 4"-5" DSB of sugar-fine aragonite sand will serve you just as well, and with less installation hassles>>
I tried to find some information on this within your oodles of articles, but couldn't seem to find anything relating.
<<Some info located here:  http://www.wetwebmedia.com/PlenumFAQs.htm >>
Is this a worthwhile exercise to perform if planning to add corals?
<<Up to you to decide...read up on both methodologies (DSB vs. Plenum) and use your own good judgment.  But for my two pennies, I would (did) go with a DSB>>
Currently I have a fish/invert system.  What kind of screen should be used overtop of the egg-crate if I proceed this way?
<<Fiberglass window screen works nicely>>
Thanks for your assistance!
Regards,
Dave Brynlund
<<My pleasure, Eric Russell>>

A bong and a blintz?
Bob,
I have been reading your book and was wondering, a plenum in a FOWLR, am I better off avoiding that, and instead use more Siporax beads, and possibly a refugium? 
<IMO, the latter... and if using a plenum, always better remoted in a separate/attached sump/refugium>
I have been told that angels don't do well in such a situation (sounds like bs to me, thought I would ask though).
<Me too... what is it about Marine Angels...?>
With a plenum, what are the chances of deadly hydrogen sulfate pockets and their release?
Thanks again
tom
>>
<Some, but slight... if the system is set up "correctly" and maintained (minimally)... with some stirring, vacuuming, no-overfeeding... no inevitable doomsday scenarios.
Bob Fenner>

Aquarium-System
Hallo Bob .
I am from Germany and I find no new article about using a Jaubert-System. I've a working 2000 Liter Tank with Stonecoralls. It's a Berliner-System. But I want to combination these two Systems. My Tank is getting bigger (I make it self every two or tree month). My problem is I don't no how many holes per inch in the Pvc (and how big). And how often must I change (not change but put new after in the downest Place / really bad English) the underground (and is that a problem for the System.). How thick and how big are the Stones small). On the top of the ground must be sand for some animals.
Thanks Michael Hannig
My English is not good but I work on it >>
>>
Thank you for writing, and your English is vastly better than my Deutschen! 
There are many types of Jaubert/Monaco plenum/live sand systems, with variations on items such as:
1) Size, arrangement of the low-oxygen, plenum area underneath. Usually people don't get overly involved in how large or many the holes might be in their bottom support, but quarter inch or so holes ever inch and a half or so will work... Otherwise look around for other chemically inert material to support the upper sand bed. There is a drawing of how this might be done stored on our site: Home Page that you might want to look at.
2) Size, type of the upper sand bed(s)... whether one, two and whether the material is graded. I encourage a larger size under a smaller, separated by a fiberglass screen material (to keep them apart, and keep animals from burrowing through, mixing them) with the upper layer being about 3 mm. in diameter depending on its depth... if smaller, a shallower depth...
3) The material making up the sand beds... should be calcareous and more "round" or spherical in profile... to facilitate even consistent water flow, discourage packing down...
Please do write back if any of this is unclear.
Bob Fenner

Plenums
I currently have a 55 SW setup, fish, liverock, polyps, mushrooms, nothing very difficult. I was wanting to expand and I bought a 110 gallon. Read up on plenum's, started assembly and was just about to install when I ran across A. Thiel's comments. Now I am truly confused/concerned. Do you currently believe the plenum is a good idea? Is it only functional if you have a way to slowly exchange the water under the plenum? I haven't been able to locate much information dated after 1998. I know you are busy but any help/comments would be greatly appreciated. THANKS IN ADVANCE!!!
Tim Olsovsky
<I think plenums are still worthwhile... given their "proper" maintenance... Much more upside than potential down. But still prefer to remote them in a separate sump... for ease of manipulation.
Slowly (or rapidly periodically, as with a valve plumbed to the bottom) moving water in/through the plenum is a good idea IMO. Do seek out and read over my friend, Bob Goemans numerous writings on these devices. He writes about them monthly in the hobby magazine, Freshwater and Marine Aquarium (FAMA).
Bob Fenner>

Sandbed question
Hello Mr. Fenner,
<Hi there>
I have been out of the hobby for about 6 years and I am planning on setting up a reef tank in the next couple of months.
<Welcome back>
I have been reading as much as I can, including some of your articles. There seems to be a big debate on the type of sandbed to use for the best results. The first book I read on sandbeds was Bob Goemans Live Sand Secrets. Mr. Goemans seems to have done a lot of research on the subject and that is why I am leaning towards using a plenum as he describes. 
<They can be a tremendous boon... done and maintained properly>
I have also read that the plenum is a trap for wastes and will eventually ending up causing the tank to fail.
<Rare, but does happen>
Instead of a plenum you should just put the sand directly on the bottom of the tank. I was wondering what your thoughts were on the subject and what experiences you have had. Thank you for any advice you can give.
<Detail to the following can be found in various places on our site (searchable): www.WetWebMedia.com
http://wetwebmedia.com/marsubstr.htm
http://wetwebmedia.com/Plenums.htm
And their associated FAQs files...
I am a big fan of the use of purposeful substrates in most all captive marine systems. Would rather place plenums in separate sumps for ease of manipulation... Bob Fenner>
Brett Bennett

Re: Tunze skimmers, Nothing To Do With Tunze Skimmers (plenums, denitrification)
I always have a lot of concerns which usually end up in a form of a question and it is very nice to find someone to ask them to. This question pertains to plenums under the tank substrate. If the water goes stagnate and air is eventually depleted as this is necessary for anaerobic bacteria to do there thing. It would seem to me to only water to be denitrified is the water in the plenum and very little exchange would take place.
<I am going to try to make this very simple, when it is actually a complicated chemical matter. Water would move between these two areas of your tank in an effort to seek equilibrium. Your main body of tank water has a high O2 level while the plenum water has a very low O2 level. But, this is all one body of water that would like to be the same across the board.>
Also I have had an idea on a system to reduce nitrates and would be thankful if you would give my your thoughts on it- Using a 55 gal poly drum, place a large foam block in the drum, the foam block would large enough to just about fill the drum, inlet and outlet would be on the top of the drum, inlet water would filtered with a canister filter to prevent solid matter from entering the drum, drum would be kept in a dark room to prevent any plant growth. Idea being center of foam block will be a denitrifier.
<Interesting idea but, I think this would become a mess eventually. Have you ever seen a trickle filter at work? No matter how well the water is prefiltered, there is always "dirt" settling at the bottom that must be siphoned out. That "dirt" is mostly dead bacteria that has sloughed off. You would have the same production of dirt in your drum but no way to remove it. FYI, you have this in DSB's too but you have worms, amphipods, copepods, limpets, etc. there to consume it.>
Do chemical substances really remove nitrates from the water and are they worth using.
<They may work, but not cost effectively.>
Thanks again, Rick Luckert
<You are welcome. -Steven Pro>

Anemone Removal
I have a 15 gallon high tank which houses a Harlequin Shrimp with his CC star, a few hermit crabs all kinds of snail, a LTA with a Pink Skunk clownfish.  I have a HOB filter (which I understand can cause nitrate levels to remain high).<Clean it at least weekly, and it shouldn't be a problem.>
The substrate is about 3-4" crushed coral (which I have read is a recipe for disaster). <Not necessarily.  With a few detritivores (not too many!) and lots of pods and worms in the CC, it can work well.>
I have 15 lbs Bali live rock.  I would like to install a plenum to help with nitrate reduction, but am unsure how to safely remove this anemone (if possible at all).  He is deeply buried and snaps quickly out of site if touched. <I personally don't recommend plenums.  No one has convinced me of any advantage over a static bed of fine sand.>
My nitrates are only about 15-20 ppm, though this is only because of very frequent water changes.  About 5 gallons once or twice a week.  I would really like to find a better way.  Ideally I'd like to remove the HOB, get more live rock.  Install a plenum with 2 layers consisting of crushed coral and live sand.  Each layer would be about 2 inches deep.  The plenum would be one inch deep and screening would separate the layers.  I would also install a small power head.  Do you think this would provide ample filtration?  That is if I can even remove this anemone. Thanks so much.  Corey <I would suggest slowly adding sugar fine sand until the bed is "filled in".  This should provide excellent denitrification, and if done a little at a time, the pods and worms will be able to resurface each time.  You could choose to either keep or remove the HOB.  This way, you won't have to disturb the anemone.  Powerheads are very anemone UN-friendly.  More live rock should not be necessary unless you desire to have it for aesthetic reasons.  Best Regards.  AdamC.>

- No Plenum, No Problem? -
Dear Crew
I have had a mixed reef tank for four years now. I regularly take cuttings from my soft corals to the LFS. My stonies however don't seem to be doing so well. I have recently been adding Kalkwasser in conjunction with a calcium reactor as I am getting 40ppm uptake in calcium per day from my massive profusion of coralline covered live rock. This seems to be turning the stonies back to growing levels as the calcium levels are now a constant 440ppm per day (alongside a pH of 8.4).
Now my question is this (changing the subject somewhat). Would having a plenum from the start have benefited my system? 
<Or perhaps just a deep sand bed... there are folks on both sides of this fence as which is "better" but I say they're both useful and worth pursuing.> 
I have ALWAYS had 10-25ppm nitrate in this system since forever. Could this nitrate level be stunting the coral growth (now I have a hammer coral that is growing nicely since Kalk additions). 
<I'd say most certainly - nitrates in any concentration above 5ppm have been known to cause problems with invertebrates.> 
My LFS (who is very well informed) says that a plenum isn't a necessity, other reefers say they are an absolute necessity. 
<Again, I think you could rework this system and push your substrate depth to about 6 inches. It wouldn't kick in immediately but it would help tackle those nitrates.>
I'll be honest it leads me to believe that nitrate isn't that big a problem in a closed system and we worry far too much about it. 
<There is much research out there that is contrary to that opinion. And more definitively, there is zero nitrate on the reefs of the world; that should be an indication.> 
Although I can see how a plenum may prevent mulm collection in dead spots, of which I have a lot in my reef system.
Just wondered what your thoughts were. 
<Please read our articles on deep sand beds, I think you'll find them most useful.> 
An experienced UK reefer who has kept at it.  Jim
<Cheers, J -- >

Cold Feet? (Plenum Setup) 4.3.05
Dear all,
<Just Ryan with you today! Sprung forward an hour, and feelin' it!>
Please help me with some advice on setting up my new tank. I am upgrading from a 70g tank to a 130g FOWLR, he main difference being that I will now have a 70g sump. I am having fun working on it and plumbing it all in without the usual inconvenience of having water in the tank.
I had decided to go with a plenum system on the advice of my local retailer, but after spending weeks reading through massive amounts of debate on the net, your site, books etc, I'm just getting more and more confused and worried about it. A main source of problem for me is getting the latest thoughts, as I don't see many new works on the subject. Loads from the 90's, such as my Tullock Natural Reef book, but not so much recently. 
<Today's SPS craze has pushed demands on water quality through the roof- And thus the technology is born and evolves. Today's use of high quality live rock, precision skimmers and or refugia, and current/wavemakers seem to have great results...But a plenum represents a simple, effective, filtration method in the right application.>
Going through all the FAQs is also confusing with different people giving different
ideas, and no dates given, though it seemed clear that DSBs were gaining favour. 
<We have recently started dating the queries. However, I don't think that the effectiveness is lost: They have forced you to visualize the entire process, in more ways than you thought possible!>
If I do a plenum system in the sump, with a lower layer of coarser 1-2mm non (less) soluble sand, and an upper level of fine sugar sand, both 2-3 inches deep, with screens between, is this still currently thought of as OK? 
<Yes>
I will be using my skimmer. Is it best to put much live rock / macro algae on the bed and use lighting? Or is it better to go without the plenum and just use a DSB?
<I'd skip either in favor of a nice circulation system and well maintained refugia. Although you haven't mentioned what type of bioload/ecosystem you're interesting in keeping, refugia opens all types of doors, without sacrificing nutrient control ability.>
Thanks in advance
Peter
Southampton, England
<Good luck! Ryan>

UGF
Question, does it matter that I have an undergravel filter plate that is not being used under my gravel. I'd like to use my live rock as my main filtration and so I disconnected my powerheads from it. I was going to take it out when I got my live rock but I was so excited upon receiving it I forgot to, does this need to go? I am afraid gunk will collect down in there with out sufficient bacteria to break it down, or maybe even anaerobic bacteria that will harm my system? Do I need to pull my rock out and take it out, I spent a lot of time creating the perfect scene?
Thanks so much I have read nearly everyone of your question answers since June 99
Clifford Ellingson
>>
Hmm, and wowzah... suspect some folks read more of my stuff than even me! 
I wouldn't be overly concerned about the undergravel filter placement... some folks in the know, actually do this sort of thing on purpose... The little bit of gunk that will accumulate there is really of no real concern... You'll no doubt have less nitrates... and other metabolite build-up problems...
Bob Fenner

One last question
do the water areas underneath the plenum need to be connected or can they be divided by the pipes with no detriment?
>>
They can be divided... though I would leave the pipe ends open and drill some holes through otherwise to allow slow versus no circulation.
Bob Fenner

NNR, possibly
Bob,
First I'd like to say thanks for such a great book, The Conscientious Marine Aquarist
I have a 100 gal tank that currently has a crushed coral substrate, about 30lbs of Fla cave rock (limestone) and about the same amount of liverock. filtration consist of a wet/dry with a mag7 for return flow, an RSB skimmer with a mag5 and a couple of power heads in the tank
for water movement. It's been set up for about 4 weeks and nitrites are just now starting to drop (0.5mg/l). Eventually I'd like to replace the damsels I currently have with a couple of dwarf angels, maybe a tang and various inverts (hermits, shrimp, snails).
I've been reading quite allot on livesand and it's ability to lower nitrates but I have a few of questions.
What's the proper way to set up a livesand bed and is there a danger with hydrogen sulfide (sp?) gas buildup?
I live near the gulf coast of Fla. Could the sand there be used or is it too fine (it's the white sugar sand)? and finally would livesand even fit into this scenario?
>>
With some careful construction, a natural nitrate reduction (NNR) system can be almost danger-free... Most involve some variation on the following scheme: from the bottom up.
1) A "dead", low oxygen space called a plenum, trapped under a couple of layers of graded substrate... but first, how to make this space? you can use PVC parts/pipe to support "egg crate/louver" (easy to cut, break with hand tools), covered by fiberglass screen material... that can be panduit/zip-tied down, siliconed on, or just draped over... 
2) An inch or two of coarser material... let's say 1/8 inch or so in diameter... covered by more of that screen...
3) and in turn covered by a few (two...) inches of finer calcareous material... graded... maybe... 1/16 inch in average diameter...
You can use naturally collected materials... sieve the stuff carefully for metal bits... And you can build, buy, rent screen sieves to grade it... and do freshwater rinse it... and maybe let it air-dry for a few days/weeks... ahead of use... 
The sand will be "live" any way you arrange it.
Bob Fenner