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FAQs on Reef Filtration: Plenums 2

Related Articles: Reef Filtration, Plenums, Biological Filtration, Marine Substrates,

Related FAQs: Plenums 1, & FAQs on Plenum: Rationale/Use, Design, Installation, Operation, Altering/Adding Media, Troubleshooting/Repair, & Deep Sand Beds, Biological Filtration, Undergravel Filters/Filtration, Nitrates 1, Nitrates 2, Nitrates 3, Nitrates 4, Nitrates 5, Nitrates 6, Nitrates 7, Nitrites, Ammonia, Establishing Cycling, Biofiltration, Phosphate, Silicates, Biological Filtration, Fluidized Beds, Bio-Ball, Wet-Dry Media 1 Denitrification/Denitrifiers, Wet-Dry Filters,

Dwarf Hawkfish (Cirrhitichthys Falco) Greg Jochman.

Jaubert System     2/10/13
Hi there guys and happy Chinese New year out of Thailand here.
<And to you!>
Anyway what I wanted to ask is the following.
I have been researching quit a bit about the Jaubert System and got very interested in it. As I am planning to install one in my new 1000 gallon system I was wondering if there is a rule on the size of this Jaubert System to have it run on a 1000 gallon system.
<A rule? The Monaco aquarium has for many years had systems several times this volume set up w/ this and modified Jaubert systems>
I have an area allocated for it which is about 50" x 19,5" which would give me an area of 6.7 Sq-feet? would this be enough?
<For the sand/plenum? Yes; should do for a moderate stocking level>
All I can find about it is the way to set it up but no real size guides as per square footage needed for what amount of water the system holds?
<Dig a bit deeper; the literature is olde, but there is much recorded/written re these ways to keep marine systems.>
Maybe you guys can help me out here?
<A search for older books is in order. Use Amazon to ferret out what is still available>
<Bob Fenner>

Plenum removal on 700 gallon system 9/27/11
Hi all,
<Hello Patrick>
My name is Patrick Laird, I've emailed with Bob a few times over the years...I am an aquarium maintenance person for a company in San Diego, and I take care of some large saltwater systems.
<As I did in time>
The particular tank I have questions about is a 700 gallon fish only system. It's dimensions are 6'x4'x4', it is very under-filtered in my opinion, and has been set up for at least 15 years. The sand bed is very deep, about 10" and is made up of mostly crushed coral, but has a minimal amount of sand mixed in. There is dead live rock (the tank has obviously been copper treated in the past), a G3 skimmer (small), a Jacuzzi brand micron cartridge filter,
<Ditch this>
UV, and a filter sock. It also has a plenum under the DSB.
<With you so far>
The tank sits below the sump. Water draws from under the plenum in two places and from the back of the tank, and is pumped directly into the micron cartridge canister, from there,
it splits to the UV and up to the sump, which is only about 30 gallons,
and it also splits off twice to returns. Water from the sump gravity-feeds back into the display. This is a really stupid, lousy set up which I did not design.
<Me neither! Heeeeeeee!>
I have taken over this service and have been maintaining this setup for about a year now. When I gravel vacuum, the most amazing amount of sludgy, pink-orange colored "gunk" comes from under the plenum. I have never changed the micron cartridge, as I cannot find a replacement filter.
<It's not there... I'd open and remove if you think it is>
I can only imagine what it looks like, and how much flow is reduced. The only pump serving all these applications is a Sequence 750 @ 3600 GPH.
<Oh! At least this Baldor product is a good choice>
There are around 100 fish in the tank, ranging from about 40 damsels to a large Imperator angel, large blue throat trigger, many tangs and other random fish.
My questions are;
- Can I remove the plenum?
<Yes, and I would>
-If so, how? i.e.; will it require me to remove the fish?
<T'were it my account, I would definitely do so... trying to "just" (with a large diameter) siphon out the existing (crap, mixed) substrate will be a monumental taskk alternatively. Best to bid, schedule and completely tear down this mess... AND make changes to the mechanicals at the same time... a MUCH larger sump et al.>
-If I remove the plenum, what will I do about the two holes in the bottom of the tank? There are ball valves right before the pump intake, but that would leave about 2' of standing water in 1.5" PVC. I know I can plug them or glue acrylic blocks on top of them, if I empty the tank. I would like to avoid that.
<I'd raise them up if you want to still use them for intakes... elbow them over to the side/s, back... paint the PVC to somewhat hide, cover the intakes with large/ish screens>
-The skimmer collects absolutely nothing. I believe this is because the plenum and canister filter catch most of everything, but am not sure. What are your thoughts on this?
<I'd wager the RedOx here is zip... I'd be talking these folks into a better skimmer along w/ all else>
Please let me know what you think, and thanks very much in advance. I would like it if Bob could answer this one, if possible.
~Patrick Laird
<Tis I, out in Fiji, but w/ some time on my hands as the saying goes, thank goodness... today. Cheers, BobF>

Hydrogen Sulfide Issues, 6/8/11
Aloha Everyone!
I am very new to the reef keeping hobby (with the sleepless nights this venture has caused I'm going to start wondering why I'm not getting paid to do this)! I spend countless hours on your site, and it is definitely a WEALTH of good information and advice for people like me, thank you for having it! My husband is always telling me to get off the computer these days, must be a sign! I am going to apologize ahead of time for being long winded. but I think that all the bits of info may help you help me!
<No problem.>
While I have done a lot of searching for answers to my questions, I cannot seem to find the answer that suits my particular problem. I am currently cycling a 125 gallon tank, which I hope one day will be a fruitful reef tank. I bought this setup on Craigslist, as it was basically in new condition and a steal, considering. I am running an Eshopps wet/dry filter with an Iwaki return pump (some research does alert me that the turnover rate is too low for this tank and I am currently searching for a new Iwaki that won't bankrupt me). I'm only getting about 6 turnovers per hour.
<Far too low, looking for like 20X turnover, this can be accomplished by the use of powerheads or a closed loop system, it does not all have to run through the wet/dry.>
That return pump is connected to a SCWD (pronounced squid) contraption that creates this wave maker like flow in the tank. There is enough pressure to push around the sand and debris at the bottom of the tank, and the dreaded glass anemones that hitchhiked on my live rock are swaying pretty hard in the turbulence. I have wonderful surface agitation as well. I am also running a Euro Reef skimmer that does one heck of a great job in this tank.
There is also a plenum on the bottom of the tank. As far as the substrate goes, everyone (including my LFS) looked at me funny when I asked for "live sand" for the bed of my tank. They gave me a kind of. don't you know you live in Hawaii. you're surrounded by sand kind of look. So against most of what I read about harvesting sand from the ocean, I went to the most remote beach I could find and scooped up two 5 gallon buckets of sand. Needless to say, I now have all kinds of critters that are still amazing me about 4 weeks into this cycle. In my opinion, the sand ranges from fine to medium grain. I have about 10lbs of live rock that I picked up from my LFS, and about 40 or so pounds of rock that we took from the beach. This is not the pitted rock you see in most reef tanks, it's just some rock that had really nice patterns of coralline algae on it that I thought would look nice while we cycled the tank.
<Sounds nice, but I'm not sure of the legality of removing stuff from the beach in Hawaii, perhaps Bob as a long time resident can chime in here.><<I'd be checking w/ the State DLNR here. B>>
I would like to buy more live rock, but until I solve this issue I will wait. My water quality is: pH 8.4; Ammonia 0, Nitrite 0, Nitrate 10, Calcium 400, KH 8, Phosphates are .25 ppm.
<The phosphates may become a problem here as an algae fertilizer.>
The only inhabitants in the tank, other than what is in the sand, are about 10 hermit crabs, some snails, some type of eel that was accidentally caught with the sand (boy was that a surprise), some tiny crabs that hitchhiked on my live rock, a couple of interesting sea slugs, a sea urchin, and some sea hares. I target feed the eel, and I drop small pieces of shrimp on the tank bed to feed the crabs. There is never any leftover food on the floor.
<With time you may start hating the crabs, as opportunistic omnivores they may start eating thing they you would prefer they don't.>
So in the last couple of weeks, I have noticed this uniform layer of gray sand, say about the bottom half inch. During my weekly water changes, I stir the sand and I notice there are bubbles that come up from the sand and a smell that comes out of the tank. There is no smell if I don't stir the sand. This layer of sand is most likely hydrogen sulfide buildup, but what can I do about it?
<Increase flow and remove the plenum, they don't really help in my opinion and just make things more difficult.>
It is very unsightly (see pictures) and makes the tank look so dirty. I want to add another couple of inches of sand to the tank, but I don't want to compact this problem even further.
<How deep is it now, it is difficult to determine from the photo?>
Due to the uniformity of the layer, I am almost questioning the construction of the plenum (it came with the tank), and if the layer of screening that was used was appropriate.
<I would not use it at all if possible.>
Most pictures of hydrogen sulfide buildup that I have seen online are spotty patches, not this uniform. Can you give me advice as to how to remove this stuff for good?
<It is determined by the conditions found within the sandbed, more water flow will help create an environment where it is less likely to form.>
My fish are anxiously awaiting the move from the 55 gallon to the 125, but I'd hate to move them if I am going to put them in harm's way.
I reduced the size of the pictures way down so if the quality is too poor, let me know and I will send you larger ones.
<Looks nice.>
Mahalo plenty for any advice you can give, and I appreciate all that you do for us!
Oahu, HI
<Dreaming of Kona...>

Substrate and plenum 07/28/2008 Hello Crew, <John> Hope you are all having good summer so far. I am writing today to ask for some advice. I will upgrading my SW tank from a 37 gallon to a 55 gallon. I am struggling to decide on what to do for my substrate. My current 37 Gallon has about 2 inches of aragonite sand, which has been somewhat of nuisance over the last 2 years. I am constantly removing a layer of detritus and replacing sand. <Ah, yes... I'd switch either to an inch or less, or four or more inches of fine/r coral sand... Please read here re: http://wetwebmedia.com/marine/setup/index.htm the seventh tray down> The 37 gallon has about 50lbs of Live Rock, several mushrooms, polyps, 2Frogspawn and 3 fish, (OCA, 6 Line wrasse and a reef chromis). I am thinking I want to bring the 55 up with an entirely new substrate rather than re-using the old stuff in the 37 gallon. <Yes, I would as well> Fortunately, I will be able to run the two tanks concurrently for a few months. <Good plan> I plan to slowly migrate my Live Rock and corals over that time. I plan to seed the bio filter in the new tank with media from the filters in the 37, and finally move all filters over to the new system. For filtration, I have a Tom's Rapids Pro PS4, without the bio balls, and a fluval 204, which I run at about 50gph pr hour to feed my Coralife turbo twist 3x UV unit. The PS4 has Seachem Matrix, Purigen, and a phosphate pad in it's chambers. The Fluval has Seachem De-nitrate and a bag of Purigen. <Mmm, I would not run all this chemical filtrant... I WOULD look into other means of better accomplishing their desired effect... a DSB, macroalgae culture... perhaps all relegated to a refugium> I also have a Hydor Korallia water pump. I will run HOB power filter and couple MaxiJets temporarily on the 55 Gallon until migration is complete. The 55 will eventually have the same filter system from the 37 gallon with the addition of another Korallia water pump. For substrate, I was planning a plenum in the main tank, as I do not have and will not have sump. <Up to you. I would> The 55 gallon was given to me with a multi plate UGF, which I was going to use for the plenum. The plan was to cover the plates with an inch of crushed coral, then a nylon screen, and 1.5 to 2 inches of fine sand over that. <... see... oh, I see this below> I have been reading over the faqs in the substrate and plenum section but I am still not sure if this solution is a good idea. I would appreciate your thought on this plan. As always, thank you for your wonderful contribution to our hobby, Regards, John <Welcome. Again, it t'were me/mine, I'd either run the fine coral sand DSB in this main tank/55 (no aesthetic drawback due to its height), or better, add a live sump/refugium, and save the big money from the chemical filtrant biz. Bob Fenner>

... Reading re plenums 7/25/08 Hi everyone!!! I have a 55g saltwater tank. I got a 125g a couple of months ago and I am taking my time with it to make sure I do it right. I am going to take down the 55g and transfer it to this tank and then convert that other one to whatever as I already have a freshwater tank. I just drilled the back for the suction plumbing and also the return plumbing. Next I am starting to build the sump. I am always online looking for DIY projects and things to make things easier as we all know saltwater tanks are beautiful but hard labor. In looking around I noticed a GARF Plenum project. It looked good but in reading on I started seeing concerns from others of the toxins that are trapped in there. On another site I saw someone had a riser on one corner with a powerhead attached. Little confused now. What's your feeling on these plenum? Is it worth the risk? Thanks Bill M <Read here: http://wetwebmedia.com/Plenums.htm and the linked files above. BobF>

Re:... Reading re plenums 7/26/08 Thanks like always. I think I will just make sure I have a 3"-4" sand bed. <... four or more> I also read somewhere that too much LR could actually be bad. Is that true. <... bad in what way?> I saw somewhere that on average you should keep 1.5 - 1.75 pounds per gallon and that overstocking it could actually back fire. <... please... read...> I ask cause I have a 24g AquaPod with a 50+ lbs of rock. Levels are a tad high but I am wondering if that could be the problem as I do water changes every 2-3 weeks. <Re this too... RMF> Thanks again Bill M

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>> 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> Dinosaur marine undergravel filter - Hey, if it works! 11/1/05 Bob. after reading several opinions from your website, it seems my undergravel filter system is out of vogue according to several experts. <Heee! Define "vogue", "experts"...> I have had this setup (twin filter plates in 55 gal tank, 2 powerhead 400's in back corners, a Skilter 400 skimmer/filter system and full length Coralife lighting). I don't want to remove my filter plates if possible. Would blocking my uplift tubes or a reverse flow system be better alternatives? <Yes... would create what "modern experts" call a plenum> What precautions should I take be bore converting to either method? <None really... could perhaps add a bit more substrate. Please read here: http://wetwebmedia.com/Plenums.htm and the linked Related FAQs at top. Cheers, Bob Fenner> Sincerely, Randy Stewart

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>

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

Plenum Vs. UG Filtration 4/1/05 Howdy Bob and Anthony. <Howdy> Anthony, I've received and read your book. Marine life is simply amazing isn't it? I have ordered your and Bob's book of reef inverts. Can't wait. <Thanks kindly!> Well, as you have both told me, I am actually running an undergravel filter instead of a DSB/Plenum (I assume due to the risers and powerheads). 55 and 33 gallon tanks. Question is, I am re-vamping my 90 gallon for my farming project and would like to know the benefits of true DSB/Plenum vs. UG DSB/plenum systems. <Ahhh... When the "Reef Invertebrates" book arrives, you will have our current opinion at great length... about 100 pages on live sand, DSBs, refugia, plants and algae!> (90 gallon used to have 4"crushed coral bed and Nitrate levels off the charts :() My UG tanks are actually doing quite well, except the pH will not stabilize higher than 8.1, buffered every day. Simply put, would you recommend DSB on bare glass, DSB on plenum with no risers, or DSB on Plenum with risers? <A static bed on bare glass is fine> I am open to any of these, I do love the looks of the DSB. I want a pH of 8.3, as I would like to do mass Xenia production in this tank. Does the rapid denitrification process of the UG/DSB really hurt my dreams of 8.3 pH, or should this be possible in time? <On the contrary... DSBs support Ca/ALK, and pH> GARF suggested the UG/DSB/Plenum, but advised removing risers at later dates. <It's a waste of time IMO> I have read article after article regarding this matter and everyone has different ideas. <Mine are backed up with the use of 48,000lbs of oolitic sand, 5,000-8,000 galls of saltwater, and over a decade of experience FWIW> I believe you and Bob come across as having the most knowledge of all who I read from on this subject. (No offense to WWM crew of course) BTW, I chopped the heads off my mushroom Sarco only to find the insides rotten. <Ughhhh! Sorry to hear it> All frags doing great, but the mother colony has these little brown "bugs" crawling around on the freshly cut stumps. I left 1 head and cut 2 heads off. All frags and momma head doing great visually. Should I be concerned with these bugs? <Its hard to say with a pic or better description than "bugs" <G>. They are likely no trouble> Broad question, I know, but these little guys are like the size of a "speck" or grain of sand. They do move around if I poke them. This is my broodstock tank and I want to be careful here. Thanks for everything guys. Your pupil, Mike Toole Detroit, MI <With kind regards, Anthony>

- Plenum in 29 Gallon Mini Reef - My new 29 g tank and stand will be in this week! I purchased a 2x65 w pc retro kit (one 10,000k & one actinic). I have a BakPak skimmer (I plan on adding a hang-on refugium in the near future also). I constructed a plenum this weekend using the plans from the GARF web-site (eggcrate sitting on 1 inch PVC covered with nylon screen). I have a couple questions about the plenum. I planned on using 100% live sand (3-4 inches) instead of the suggested substrate on the GARF site. Will this be a problem? <Probably.> Will the sand stay on top of the nylon screen or will it eventually work its way down into the plenum? <It will work its way down in time.> Could I, or should I use a thin layer of crushed coral directly on top of the plenum underneath the sand bed? <Yes.> The DIY plans call for a second layer of screen to be placed in the middle of the sand bed to avoid disturbance to the system. <Correct.> Is this second layer of screen necessary in your opinion? <Yes.> Also I plan on adding approximately 30 lbs of live rock. Should I add the rock and sand at the same time? <Yes.> Thanks for your help. I'm trying to get all the help I can to avoid too many alterations in the future. <Honestly, I'd skip the plenum in your case - you just don't have enough volume in the tank to sacrifice this space, and because of the small size of this tank is going to give a net effect of almost zero. I think you'll have more problems than solutions with this setup. Would be better off just doing a deep sand bed with live sand and use the live rock.> Thanks for maintaining the great site. <Cheers, J -- >

Type and depth of sand for a plenum Hi, first time writing in so a little nervous, please be gentle. Have read many articles on WWM, in fact so many that I think my head is going to explode. My question is about my plenum, I had a plenum system 55g, setup for 4-5 years, everything was great, but then things started to die off, the coralline and fish etc. so I tore down the system cleaned out the plenum and put it back in, with 2" of crushed coral on top of the plenum and NO sand. << I'm not sure the plenum was the problem from the first time. I don't think I would have removed it and started over. >> Now I know from reading at WWM that this is the wrong way to do it. So my question is this, can I just add the sand right on top of the second screen, on top of the crushed coral? << Sure can. >> Or do I need to tear it down and clean the crushed coral (replace?) Will the crushed coral be full of gunk that I need to clean out first? << Was the crushed coral used in the tank previously? If so, I'd probably take and wash it out. If not, then don't worry about it. You can add sand right on top. I'd do this slowly adding a half inch at a time. It will slowly work its way down and go beneath the crushed coral. >> Or will putting the sand on top be ok? It has been up and running the way it is now, for close to a year, no sand on top of the plenum, so I wasn't sure if just putting the sand on top would be ok, or if it would just trap a bunch of gunk that is in the crushed coral. << If it has now been up for a year don't do anything. Just let it keep going. >> Also one other thing, you talk of a DSB needing to be 4+, why does a plenum setup not need to be that deep, I am assuming because of the plenum? << I would still have it that deep. I think 3" is perfect with or without a plenum. >> Does the sand on top of the plenum need to be deeper than 2"? << I don't know if it needs to be, but I think it will do better if it is 3"-4". >> Ok I think that about covers it. Thanks for your help and I love the site. Thanks, Robert Cline << Blundell >>

Removing undergravel filter Experts of WWM: <Hi Ron, MacL here with you tonight.> I have recently been doing research about the removal of an undergravel filter from an already established FOWLR aquarium. (I'm going to leave out all the useless details, of course.) Anyway, the tank has been set up for a year and a half and all inhabitants seem to be doing well. The U/G filter has turned into a nitrate factory, as I've learned they always do. What I would like to do is to remove the uplift tube and cap off the plate. I have only been able to find one instance (this site) of this being done, so I am extremely worried about doing this. Anyway, that is my only question. can this be done without a die-off of aerobic bacteria, or cause any type of bloom? <Anytime you disturb your sand (or crushed coral or whatever bed) you will experience some die off. You don't mention what other type of filtration you have, I'm assuming you have something to handle the filtration once you stop running the undergravel? That being said that you will have some die off the idea is to minimize the amount of die off. If you can move the sand from around the tubes, then cap them then move it back without disturbing the sand or crushed coral in other areas you have a better chance of minimizing the effects. I think you should be prepared to do a water change in a couple of days regardless depending on the other type of filtration you will be going to. The way an undergravel filter works is pretty simple, it pulls the detritus down through the sand hopefully to end up under the undergravel where the bacteria attacks it. For this reason, once that water stops pulling down you are definitely going to have some changes going on within your tank.> Here are my tank specs: 30 Gal AGA, 96W PC 50/50, Prizm Skimmer with surface skimmer attachment, 40-50lbs live rock (40% Tonga, 60% Fiji), 2-3" crushed coral over U/G filter, powered by Penguin 550 Powerhead. <If you are going to try to go with the Berlin method where the tank is filtered by the live rock then you are going to need the power heads in the tank for oxygenation. If that filtration isn't already established this is going to become much harder to do. Meaning if you don't have bacteria built up in the live rocks and in the crushed coral. This may definitely mean water changes as the tank adjusts to the change.> The inhabitants include: Small yellow tang (to be moved to larger tank at later date), maroon clown, yellowtail damsel, bicolor Pseudochromis, scarlet skunk cleaner, 2 Astrea conehead snails, unknown amount of margarita and abalone snails, as well as blue leg hermit crabs. <Ron I don't want to discourage you, I'm just trying to make you understand the reality of this undertaking. Let me try to simplify a bit. If your tank is already being filtered in the majority by the live rock then a switch won't be quite so hard. BUT if your tanks primary filtration system is the undergravel then when that stops running you will have some changes take place within your tank. You probably will have an ammonia rise but that can be handled cautiously with water changes in order to put less stress on your fish.> Thank you very much, if only for simply reading this.. <I hope I have helped, if you wish to get into this discussion further or have any questions just let me know. MacL> -Ron Narozny, Jr. Abandoning an UGF in a newly set-up 90 gal marine tank and feeding triggers Hi gang,<Hi Ed, MikeD here> I think you guys are doing a wonderful job.<Thanks, we try> My question is I have a 90 gallon fish only that has been up and running for 1 month, it took 3 weeks to cycle,<Be careful. in that short a time even the tiniest glitch can cause it to re-cycle or go into a mini-cycle.> the first question is I put an UGF in before I saw your site, I have 2 300gph power heads running on the up tubes, is this ok or should I get rid of the UGF, I have 6 inch crushed coral covering the UGF, and is it ok to just pull the tubes and cover up the holes without removing the UGF.<This would be my suggestion. I've done it in the past with no problems. On an olde tank you might have sufficient accumulation beneath to warrant siphoning out the mulm, but here I suspect you'll be fine> Second I have 2 trigger and a coral beauty<2 triggers can be a bit much in a 90 as they grow, so consider yourself warned> that are carnivores, I have found that our local Wal-Mart store has in it's sea food section what is called sea food melody, the guy working there said it's just left over and it has squid, clam, crab, and some sort of fish, all raw and unprocessed, I gave ground some up in the food processor and the fish love it.<It makes an excellent food as long as you don't grind it too fine, where it can pollute the tank. Your triggers, for instance have very strong jaws and sharp teeth. I just cut it into small pieces with scissors and feed until they lose interest, then stop> Is it ok, should I add some vitamins?<You can> Last question is I was given some what used to be live rock which I bleached and washed and left out in the hot West Texas sun to dry and let the bleach dissipate, I put it in the tank with my 25 lbs of live rock, I was told it would become live again over time, is it ok to do this?<Yes, it WILL eventually become part of your LR as well> I was told it would be ok, well any way I read your site daily and enjoy it very much.<Thanks for your interest and support> Thanks Ed from West Texas.

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 ? 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>

Reworking An Existing System-Trials And Tribulations Thanks for the comments and the link. <My pleasure! Glad I could help!> I was recently counseled by a pretty reputable local dealer to leave the plenum alone because disturbing it would release all kinds of chemicals I don't want in excess in the system so leave it be. I don't think that's a good idea. I believe this could be remedied with activated carbon in the sumps. The other option is shut off one tank at a time, completely drain it, Rip the plenum out hopefully without damaging the glass and replacing it with course crushed coral and live rock, and add ~ 92 Gal of New Salt water to the system. HELP!!! <Well, I would be inclined to agree with this guy, actually. My biggest concern is releasing potentially noxious compounds into the water after disassembling the plenum. If you are so inclined, I would consider this a complete "breakdown" of the system, and treat it as such. That means removing everything, executing the massive water changes that you mention, as well as some good mechanical filtration to remove as much of the detritus )which will no doubt be released into the system as a result of this activity) as possible. I think you pretty much have the rest of it wired...don't forget very aggressive protein skimming, too. Also, be sure to monitor ammonia and nitrite for some time after the procedure is completed, and don't add any new fishes or other livestock until the tests confirm all is stable...> Side note-The first sump is loaded with Aiptasia. I've been adding peppermint shrimp to the sump but I don't see the shrimp actively eating anything. I could pull the Caulerpa out and try to pull them off or use something to make them release (Fresh water dip???). But I would be taking a significant nutrient reducer away from the system. If the freshwater did would work without killing the Caulerpa that might be a feasible option. <Well, Caulerpa can leach some chemicals into the system if ripped or otherwise stressed. I'd opt to remove all of the Caulerpa and go with my one of my favorite "purposeful" macroalgae, Chaetomorpha linum. It's every bit as efficient as Caulerpa, but with none of the "dark side" that you need to be aware of when utilizing Caulerpa. I applaud you if you were referring to the Aiptasia when you were talking about removing a "significant nutrient reducer" from your system. These animals are very efficient at processing nutrients. In fact, Anthony Calfo, in his "Book of Coral Propagation", suggests a novel use for excess Aiptasia: use them as a natural "scrubber" in a dedicated raceway, channeling nutrient-laden water into a field of these anemones. Very cutting edge; very cool, if you ask me!> I also have green and red Cyano bacteria breakout occurring ( High Phosphates??) This seems to happen when the CO2 stops releasing into the Calc reactor. Right know I have the Calc reactor off for the night cycle. Don't know if this is adding to the problem. <Well, it is possible that it can be contributing to it...> I believe there is enough aeration in the sump and enough photosynthesis for me to do continuous run with the calc reactor without dropping the pH significantly. I don't have a pH or kH probe and I don't know how good my judgment is with the liquid test strips. <An electronic pH meter is a good investment if you're gonna use a calcium reactor..> So far I've been watching the tanks for positive response to my adjustments. According to the kits I use I would guess kH to be low and pH to be 8.4 the upper limit to where you want to be. Calcium ???. <Ask a dozen people, you'll get a dozen answers. My answer is at least 350ppm> I believe the high iron content of our water to be a contributor to the hazy colors I get from the test kits. I started pretreating all my water with carbon to try to reduce the iron and it appears to be helping. <RO/DI is a great start to prep source water...> About our water. Our water is so hard that if you let it sit with circulation you will have piles of iron and carbonate precipitates on the bottom and sides of the tank. Precipitates so hard they have to be removed with a metallic scraper. <THAT's hard, ladies and gentlemen!> If I go a RO unit to deal with this I would anticipate about a quarter of the expected life from the filters in this type of system. <That's being optimistic!> What fun. <Ain't it, though? Good luck! Scott F.>

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.>

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 Practices! Hi <Hi there! Scott F. at your service!> Just found your Q & A site brilliant, can't find answer to my question which is about plenum filtration: Rena plates, you know the ones that snap together, if I lift them up on plastic tubes to make an inch water gap, use some plastic screening to seal the front edge (tank is a 55 gal bowfront Juwel) of the filter bed cover with coral gravel then another screen then coral sand would this produce the same effect as the egg crate plenum system. The only difference I can see is that I would not be covering the top of the Rena plates as they only have small slots in them, the 1st plastic screen would only be placed in the front to seal the filter bed where the plates don't fit snug to glass because of the bow. <Just be sure that the window screen material "overlaps" the plates and extends as close to the front glass as possible. Also, you could expand the size of the holes on the plates. Sounds fine otherwise!> I could then use the up lift to start the bacteria process once established remove power head and up lift and monitor system before adding live stock. <Your idea sounds quite workable. Just make sure that you follow the generally accepted principles of plenum construction (i.e.; height of sand, void space, etc. These have been developed after much testing, and generally do not work well when we "improvise"!> Other filtration for this fish only tank as well as the plenum would be: 1 Fluval 203 canister filter with spray bar the Juwel filter system (foam pads and power head) 1 extra power head for circulation (not filtration once removed from plenum system) How far off am I?? Yours, Chris <Actually, Chris- it sounds like you're on target here! For a lot more on plenums, check out Bob Goemans great site- saltcorner.com. Lots of good information from one of the leading hobby supporters of the plenum method! Have fun! Regards, Scott F>

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>

Plenum, Yes! Jawfish-No! Bob, <Scott F. on call today> I have a 75 gallon reef tank with a plenum. It has been working very well. I would like to add a blue spotted jaw fish to the tank, but I'm concerned that even with the protective screen below the first layer of sand the jaw fish will disturb the plenum system to the point of severe problems with my system. What do you think? <Your concern is definitely valid. Even with the plenum screen in place, It is too disruptive to have this fish in a plenum-equipped tank, IMO. I'd rather keep these guys in a separate aquarium assembled just for their special needs. The fish will do better, display more readily, and both you and the fish will be happier in the long run. Good luck! Scott F.>

Planning A Plenum! Hello WWM crew, <Hello! Scott F. here with you> I am in the process of changing sumps on my 130 gallon reef tank. I have finished glazing a 40 gal tank to be used as a Jaubert Style plenum. My question to you : I purchased an undergravel filtration plate to operate as the plenum, rather than using pvc and egg crate. <To be honest, I would not use the UG filter plate. My concern is that these plates may not have enough slots and holes on the surface. This could restrict the diffusion of nutrients in and out of the plenum, and could create long-term problems. I'd really go for the egg crate. Make sure that the plenum area height is around 1 to 1-1/2 inches, BTW. > The UG plate fits lengthways perfectly, but there is a 2" gap either side width ways. <I would not be overly concerned about that gap. Just make sure that the screen is "folded" in such a way as to prevent more sand from getting under the plenum.> I intend to use netting to cordon off the plenum, and divide the sand layers, so would this gap either side reduce the effectiveness of the plenum / render it useless ? I personally don't think that a 2 inch gap on each end would be disastrous. I'm more concerned about that UG plate, actually> Also, in terms of substrate and layers, I intend to lay a 3" deep layer of coarse sand first, cover this in netting, then add a top layer of finer sand, which will be populated by sand churning critters - does this sound correct ? <I'd use the "traditional" 2 inches of depth for the layer atop the plenum, then add the screen, and top layer of sand. It's really important not to "improvise" the plenum construction. The plenum depth, sandbed depth, etc. were developed after many years of research by people like Jaubert, Goemans, and Gamble. These numbers do work! Lots of people who claim that plenums "don't do the job" often have not followed the "blueprints" for its construction. Don't be one of them! Frankly, I'd avoid large populations of sand-stirring creatures in the plenum system. Too many of these animals can convert some of the anoxic areas of the sandbed to aerobic ones, which can drastically reduce the efficiency of the system. If you are concerned about excess detritus in the sand bed, you can very lightly siphon the top 1/2 inch of sand, but I would not go deeper.> Thank you guys Andrew Hough <And thank you for stopping by, Andrew! Do check out Bob Goemans' web site, www.saltcorner.com, for more information on plenums from the master himself! Good luck!>

Nutrient Export, Plenums, And More! I have some high Nitrate (80mg/l) and phosphate (3mg/l) problems in a 24month 80gallon set up. (Hope my conc. units are right). The setup gets a 5-10% water change on a weekly basis and is stable with a medium/high load of eight fish, two shrimp and a blue lobster. I tried to introduce an anemone but it never fully open and unfortunately starved. I also have a bubble algae problem. (The set up is in two tanks 55gallon which cascades its water to a 30gallon tank which then returns to a wet/dry sump in the basement with protein skimmer, mechanical filter, carbon, heater UV then back to the 55gall tank) So. my two questions. 1. Will I realistically be able to get phosphate down to a reasonable level for anemones and reduced algae? What should I aim for and will aluminium oxide be the most economic route. The phosphate comes presumably from accumulation from food. <Well, ideally, you want to shoot for <0.05mg/L on phosphate, and less than 10mg/L nitrate, if you can. I think that it is certainly possible to lower phosphate in your system. I think that there is certainly some phosphate coming from food, but there is also probably some phosphate in your source water. If you aren't using one already, you should look into an RO/DI unit, which can help you start off with more pure water. Another thought is that the mechanical filter which you are using needs to be cleaned (or have the media contained within it changed) more often (maybe twice a week). High nitrate and phosphate are definitely signs of nutrient accumulation. Attacking both together is possible. Your goal here should be to maximize nutrient export mechanisms. Your water change schedule is good; you may even want to try 2 smaller (5%) changes per week, to dilute the nutrients before they have a chance to accumulate. Also, try to really adjust your skimmer until it yields at least a couple of cups of dark, yucky skimmate a week. It may take a fair amount of tweaking, but it is possible to get good results if you work with it. I'd employ extra chemical filtration media, such as PolyFilter (my personal favorite). This stuff really works! Make sure that you are using a high-grade, phosphate-free carbon, and change it regularly. Another though would be to employ "purposeful" macroalgae, such as Chaetomorpha, Gracilaria, or Halimeda, and harvest them regularly. They will utilize many of the same nutrients that your nuisance algae are-and they will ultimately beat out the lower algae. Harvesting them essentially removes nutrients from the system directly...yep- it works!> 2. I have tee'd off a connection from the wet /dry to a 80gallon 40x20" footprint Rubbermaid container which will act as a plenum (or it could be a refugium) and new sump. The water will be pumped back to the wet/dry on a recycle loop. I am planning on using 160lb of aragonite coarse coral mix as a 4-5" bed over a 1" plenum space. <Well, a plenum is a very useful tool if constructed correctly. It does require specific void space, particle size, etc, so do read up carefully if you plan on pursuing a plenum setup. Don't deviate from the established methods for constructing plenums- the techniques and guidelines were developed after a great deal of research. Check out Bob Goemans' web site (saltcorner.com) for much more on plenums. Bob is the authority on this system in the U.S., and can really give some great input! If you opt for a remote deep sand bed without a plenum, try a fine, oolithic aragonite like Carib Sea's "Aragamax" Sugar-Fine sand, and shoot for 4 inches or more.> I have read that the plenum relies upon slight convective currents to effect as large an anoxic denitrifying layer as possible. Also since the sump/plenum is in my basement I am concerned about temperature control. I figure that I will put 30ft of 150W heating cable under the aragonite to deal with heating needs and achieve some convective mixing through the aragonite bed. Do you think this will work - will it be beneficial? <To be quite honest with you, I have not seen this done before...It is an interesting idea, but I'm not sure whether or not it is worth the effort...I'd really encourage you to contact Bob Goemans on this one!> The reason I started thinking of the cable heater is that the plenum will be in my basement which is about 40degF at the moment and only 50-55 in summer. I live in New England. I figured that the Rubbermaid tank itself (even although it will be insulated) would need some degree of heating and then subsequent small power head or air lift to get some recirculation. <Absolutely...I agree> However this would NOT help the maintenance of temperature within the aragonite bed which would depend upon conduction for its heat from the main liquid bulk. Next I figure that the microbiological rates are probably favored by maintaining a reasonably high temperature 80degF (not necessarily trying to seek thermophilic organisms). Therefore I have to find someway to keep the substrate at80degC. <Very logical approach> Cable heating is used here and there for encouraging plant growth in non-marine aquarium and this suggested to me what might work as a possible solution together with enhancing some flow through the sand bed. All the reading I have done to date - as you states - suggest some but only a slow vertical flow of water through the bed is recommended for the plenum to maximize its anoxic layer. However no where seems to suggest what is too fast or too slow. <Well, as you would probably agree-the faster and more efficiently that nutrients are turned into energy, the better your water quality will be. So, it's important to create a system to foster these process...I do see the logic in your method...very interesting!> Even with my proposed setup I will not know what vertical linear flow rates I will be achieving anyway. My intent was to concentrate the heating cable into three longitudinal strips so that there will be cold:hot:cold:hot:cold:hot:cold strips the length of the tank (hope this is reasonable explanation). I will be using 110VAC roof de-icing cable. (I have ground fault trip electrics and will be very cautious). The cable is water proof and fully plastic coated therefore should be okay for continuous immersion. <I have no experience with this device...do proceed with caution if not using an aquarium-specific heater cable system...> Initially I intend on leaving the cable on 24hours but could put this on a timer if the mass transfer does not seem to show that the plenum is doing its stuff of removing nitrate. However I will wait 12months to be sure everything has had a chance to mature and monitor concentrations along the way. <Sometimes standing back and letting nature do its job really is the best procedure> I must admit that I was torn between setting up a refugium in place of the plenum and instead using plants and light. Do you think maybe I should do half and half and plant Caulerpa (sorry about the spelling) with a plant spectrum 24" florescent tube on one half. <I am very anti-Caulerpa for a variety of reasons- I'd use different macroalgae for this purpose...but do utilize some macroalgae. Perhaps you may want to employ a "non-plenum" DSB in your main system, and add the refugium in line? Just a thought...> However - if I do then I will not know if the main idea ever worked.... <Ahh- the joys of experimentation!> Lastly, my skimmer is a CPR BakPak which is a small footprint venturi in-sump skimmer but only rated to 50gallon. I have not had a chance to read through all the skimmer stuff you and others have posted here - but I did see the stuff Snailman posted and this sparked enthusiasm to do this next. However I do need to finish and get this plenum up first. <Well, a skimmer is so vital to your system that you may want to push the skimmer up to number one on your list...The Bak Pak is a great skimmer- but I think it's operating at the edge of it's range in this system, so an upgrade is highly advisable here!> Lastly, lastly I did not add in the previous email that before the plenum I will be putting in a 30gallon trash can with flow distributor filled with polystyrene peanuts to act as a trickle filter to also increase my ammonium denitrification. The water will drain through the trash can trickle filter by gravity into the plenum. Currently my ammonium is 0.2-0.3 (don't know the unit) but anyway low range but detectable. I figure for minimal expense I could get more aerobic degradation. I built this piece ahead of deciding on the plenum which will presumably also achieve the same end effect of further NH3-> NO3 oxidation in addition to the anoxic denitrification. I have read elsewhere that this is not recommended as enhancing the NH3 oxidation will increase my NO3 problem. <That's my thinking...> This seems logical but at worst case if all the NH3 is shifted over to NO3 - I am only looking at a small increase in NO3 to my current concentration. Thanks for your comments and any further thoughts are appreciated. <Well, you certainly have some great ideas and a nice approach! I think that simple, biological-based systems are always best. You will be surprised at how a simple idea, such as a deep sand bed (with or without a plenum), a great skimmer, good husbandry, and live rock can do the trick. Check out Anthony Calfo's "Book of Coral Propagation" for some more information on the concepts that you touched on. Also, You may want to pick up "Live Sand Secrets" by Bob Goemans for a simple review of plenum dynamics. Most of all-Have fun! Good luck! Regards, Scott F>

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 >

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>

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