Plenum - To Plenum or Not to Plenum (This is the question)

Discussion in 'Biological/Natural Filtration and Deep Sand Beds' started by Nemeziz_za, 26 Oct 2012.

  1. Nemeziz_za

    Nemeziz_za

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    Hi Everyone,

    I am going to add a DSB (external in a sump configuration) as one of the building blocks to my biological filter on my new build.

    My question is aimed at people who;
    • Formal tertiary qualification relating in some form to the question
    • Have run a DSB with or without a plenum
    • Have had first hand exposure to a system that used or is using a DSB with or without a plenum
    • People who still feel they are qualified to answer are of course welcome to, provided you give details why you beleive yourself to be qualified

    :tt2:

    The reason I have targeted the respondants is that there is too much info that is unsupported and merely debate for the sake of the debate.

    I want to create a fantastic South African built and managed mixed reef tank that will some day grace the pages of TOTM. To do that I want to source the best practical information I can.:yeahdude:

    P.S: If anyone needs additional info to better answer my generalised question fire away
     
    Last edited: 26 Oct 2012
  2. AdS Guest




    to hide all adverts.
  3. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,771
    Likes Received:
    582
    Location:
    Sandton
  4. Nemeziz_za

    Nemeziz_za Thread Starter

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    I have read it thanks and its 10 years since. I was also very fortunate to have been to that aquarium ;)

    I'm looking to get information 1st hand from people who have run one for 5,10,15,20 years. This is not a new conversation like LED or dare I say it carbon dosing or Zeo. This is a practical well written and accepted methodology which has a 15 years of data.

    Too many forum posts contradict each other at least there seems to now be an accepted particle size. However flow, inhabitants, maintenance and husbandry of a DSB are still heavily debated.
     
    Last edited: 26 Oct 2012
  5. jacquesb

    jacquesb Retired Moderator

    Joined:
    29 May 2007
    Posts:
    17,868
    Likes Received:
    69
    Location:
    Cape Town
    Hi Nemeziz_za - this is now the third time I am try to post this - hopefully third time lucky! ;)

    You definitely don't want a plenum, because you will stop 80% of the working of your DSB. A plenum delivers oxygen rich water to the bottom of the DSB.

    You don't want that, as the bottom part of a dsb is where the anaerobic bacteria does their work. They break the nitrates up into nitrogen gas and oxygen gas, which escapes as gas bubbles into the air.
     
  6. seank

    seank

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Uhhmmm, what is a plenum?
     
  7. jacquesb

    jacquesb Retired Moderator

    Joined:
    29 May 2007
    Posts:
    17,868
    Likes Received:
    69
    Location:
    Cape Town
    LOL Sean. It's an AGE old technique (I think this stems from the 70's when keeping marines had a different "technology" to today)..... It was an uplifted section BELOW your sandbed (ie. using egg-crate, or an old type undergravel filter) and having water pumped below your sand bed - well - actually - EXACTLY like the old "undergravel filter" idea!
     
  8. seank

    seank

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Ahhh, the ones we used in our freshwater tanks......
    Ok, then I too have plenty of experience @Nemeziz_za, fire away with your questions....lol
     
    Last edited by a moderator: 26 Nov 2015
  9. naptalene

    naptalene

    Joined:
    6 May 2007
    Posts:
    365
    Likes Received:
    4
    Location:
    Randburg
    No water pumped through, just a raised layer above the glass :)

    I'm interested to see if anyone answers whose been running either for a long time.
     
  10. Lord_Blackadder

    Lord_Blackadder

    Joined:
    10 Apr 2012
    Posts:
    1,642
    Likes Received:
    131
    Location:
    Durban
    You're not going to find anything concrete because it's a very subjective topic and difficult to test. I had a plenum system when it was all the rage about 15 years ago and I still had nitrate issues. Since I've been using a DSB with no plenum, nitrates have constantly been in check.

    I've experimented with a variety of substrate particle sizes and materials. I've had the most success with sugar sized particles. Material doesn't really matter. I've used playsand for the last few years and haven't had any problem with it. It doesn't compact after a few years like aragonite tends to do. I recommend adding about 10% estuarine mud to kickstart it. You also want maximum biodiversity. I use about 20% live sand from local waters at least 5m deep to avoid tidal species, though since you're in CT you won't have much of a survival rate due to the water temperature difference.

    I find a moderate flow rate is best. There isn't much point making the DSB deeper than about 12-15cm if you're using sugar-fine substrate. The anaerobic zone starts at just a few cm below the surface, as evidenced by the dark coloured sulphides that form. In my current reef tank I've topped the DSB with a 1-2cm layer of coarse crushed coral, live rock rubble and macroalgae to encourage pods and other scavengers.
     
  11. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,163
    Likes Received:
    1,232
    Location:
    Centurion
    Mine is the same. Some empty snail shells provides plenty hiding space for bristle worms.

    hmmm, depends. Somewhere recently somebody set one up here on MASA were a airline hose is inserted at the one end into the plenium. It is then allowed to siphon over into the return chamber. Using a air valve, he restricts the flow to a drip rate. What happens then is that he creates a slow but steady pull of water down into the DSB. Allowing more flow into the anaerobic section. For him it seems to work very good.


    me too. Do not have access to that volume natural sea sand either and cannot do that volume aragonite either. Also due to being in Gauteng I do not have access to live estuarine mud. You in Cape Town will have colder water mud, so nope, not option for you either.

    Flow should be so, that it gives a water head of between 6 and 10mm over the divider. That means the distance between the top of the glass and the actual water level. Lower than 3mm and you will have excess settlement on the sand. Higher than 10 and you will cause sand storms, especially at the entry side.

    Lastly
    Sorry, I'm a IT specialist,no formal tertiary qualification relating to marines
    I do run DSB's since I started marines but without a plenum
    Have had first hand exposure to a system that used or is using a DSB but without a plenum
    And I do still feel qualified to answer. Why, When in Centurion, come check my remote DSB.
     
  12. belindamotion

    belindamotion Google Master

    Joined:
    24 Jan 2011
    Posts:
    4,803
    Likes Received:
    134
    Location:
    Pinetown,South Africa(KZN)
    http://www.marineaquariumsa.com/showthread.php?t=34671

    You might want to go thru some of Paul B 's Threads...
    http://www.marineaquariumsa.com/showthread.php?t=27673
    http://www.marineaquariumsa.com/showthread.php?t=35260

    His Tank has Reverse Undergravel Filter (RUGF) ...40yrs later and still going..
    http://www.marineaquariumsa.com/showthread.php?t=18200
     
    Last edited: 27 Oct 2012
  13. Bob the (reef)builder

    Bob the (reef)builder

    Joined:
    7 May 2007
    Posts:
    1,779
    Likes Received:
    32
    Location:
    Joburg
    Not sure that anyone here i's talking about a plenum. It is not a reverse undergravel system and it does not create an aerobic zone under your dsb. I am pretty sure that the only study that I read about that was remotely close to being scientific showed no benefit to a plenum over a normal dsb.

    I ran a pretty successful tank for about three years with a remote dsb with plenum, but if I did it again I would not bother with the plenum part.

    Good luck with the tank Nemeziz.
     
    Last edited: 27 Oct 2012
  14. Nemeziz_za

    Nemeziz_za Thread Starter

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    Hi Everyone many thanks for your individual responses to my question. I will break my reply up to make my life simpler. ;)

    Plenums
    A Plenum is not an undergravel filter, although the UGfilter plate as an item is often used in smaller systems to create a plenum. As @naptalene and @Bob the (reef)builder rightly pointed out.

    A plenum is simply a open space below the substrate. That’s the low Oxygen space where the bacteria convert Nitrate to Nitrogen gas.

    without the nitrate consuming plenum, there is really no point in including a DSB in your system. Was a statement I read a few times in my travels over the interweb, however it is a subjective statement with no supporting data.

    What are the benefits of a DSB? When it is used as part of a Jaubert/Plenum Filter, it seals the plenum and allows the anaerobic bacteria to convert the nitrates in the tank water into a harmless byproduct, Nitrogen. is as simple an explanation as can be given to support the Plenum with a DSB.

    The popular Live Sand Filter is the brain child of Dr. Dean Jaubert. This innovative filtration system consists of a Deep Sand Bed (DSB), a plenum and a protein skimmer. Each of these components is an integral part of a complete biological filter, converting ammonia to nitrite, which is converted to nitrate (via aerobic bacteria), which is in turn converted to nitrogen (via anaerobic bacteria). This has been improved upon with the introduction and understanding of the value Live Rock brings.

    One sets up a plenum with a box made of one-inch diameter PVC pipes of a size that nearly covers the bottom of the tank or sump. You place a Nylon screen to the square shape of PVC and place a 7 to 9 cm layer of sand that’s of a grain size too large to fall through the screen.
    Like the above, those 7-9cm are where the Nitrite to Nitrate bacteria live, and the open water beneath the plenum the low Oxygen bacteria reside, converting that Nitrate to Nitrogen Gas.

    Plenums in my research have received subjective credit in systems with a larger bio load such as fish populations.

    DSB

    Questions regarding how effective deep sand beds are in a reef aquarium. ANAMMOX bacteria grow relatively slowly compared to aerobic bacteria without a carbon source, but when the scientists add acetate (vinegar) this greatly increases their effectiveness for reducing excess nutrients in the water column. Perhaps dosing vinegar in a reef aquarium with a deep sand bed will increase nitrate reduction to where it is a much more useful tool.

    @RiaanP I respect your comments as I have seen you post a number of well intended and informative posts. I also spent some time researching ATS and found your posts and thread. Exactly the type of person Im hoping to hear from.

    @Lord_Blackadder and @Bobthe(reef)builder; both your posts summarised my many many MANY hours of reading on this matter
    This was supported by a number of articles I read and offers support for differing bacteria and fauna. This practice seemed to have more direct support then a Plenum ;0

    Two sites for some detailed yet reasonably concise information
    Deep Sand Beds
    Ron Shimek's Website...Deep Sand Beds
     
    Last edited by a moderator: 26 Nov 2015
  15. Nemeziz_za

    Nemeziz_za Thread Starter

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    @belindamotion

    I still need to follow your links and read them, I just didnt get the time as I had 26 tabs open in my browser I was wading through and couldnt face even more at the time ;) (thanks Google)

    Im however done with those and now its onto your, thanks for sharing the links.
     
    Last edited by a moderator: 26 Nov 2015
  16. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,771
    Likes Received:
    582
    Location:
    Sandton
    how is your decision making coming on?

    i spoke to Julian about this when he was here in SA, will look for my notes if i still have them, but i dont think technology override tried and tested. but i am very keen to setup a 3ft experiment tank and see how it fares
     
  17. Nemeziz_za

    Nemeziz_za Thread Starter

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    @dallasg Seems we were posting at the same time. :thumbup:

    I was gutted when I heard he was here and it was an event that had already happened, I couldn't believe I missed the opportunity. I still cant :dft004: Would be amazing if you found the notes and could share them with us.

    Im tempted to consider planing 2 x DSB 1 with and 1 without, but trying to make it a controlled experiment whilst having fun is escaping me for the moment.

    Right now, just because Im stubborn and I can not find any information that supports not having a Plenum, Im probably going to include one. Its additional planing and implementation time at the worst IMO currently.
     
    Last edited by a moderator: 26 Nov 2015
  18. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,163
    Likes Received:
    1,232
    Location:
    Centurion
    just note that although you do get bacteria in the open water, or in the open space of the plenum. There are a lot more bacteria living on any medium. So the plenum, although originally used, fell away.

    Depending on your substrate, 150mm is generally the depth used for playsand.

    Lately, DSB got replaced by NP-pellets. But that cost more, as in the reactor and replacement medium. Yet, it takes about 6 weeks to be 100% effective. The DSB can take 3 months or more, largely depending on how you seed it. The last month or 2 it is now Orca cubes. Being promoted as the cure we all been waiting for.

    But does not matter what biological filtration method you use, each one do have its advantages and problems.

    I am happy with my DSB and see no reason to rip the heart out of my system.

    I'm coming down to Cape Town soon for a week or more. Just waiting for the boss. Maybe we can sit down one evening, chatting, scheming, planning....
     
  19. Nemeziz_za

    Nemeziz_za Thread Starter

    Joined:
    25 Sep 2012
    Posts:
    1,584
    Likes Received:
    39
    Location:
    Durbanville, (Cpt)
    @RiaanP

    Pellets flow, cost, clogging, on comes Cubes to solve the problem, I agree with you each has its advantages. I am sold on the DSB and reading up with supporting documentation it appears that carbon dosing will speed up the curing of a DSB. http://www.patoczka.net/Jurek%20Pages/Papers/Anaerobic%20vs%20Aerobic%20Treatment.pdf


    That would be amazing man, keep me posted could even sponsor you a dinner or at the least a beer at the house and show you round the proposed tank site ;)
     
    Last edited by a moderator: 26 Nov 2015
  20. Gummi Bear

    Gummi Bear

    Joined:
    14 May 2010
    Posts:
    383
    Likes Received:
    1
    Location:
    South Africa, JHB, Mayfair West
  21. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    I have not commented in this thread mainly because i am not a fan of a DSB. I have run many DSB type setups and never could i get Nitrate down to an acceptable level. Possibly because i expected to much or the bio load was to high. I am a denitrator fan. However IMO there is one member that has written quite a lot on DSLB. He calls it a deep sand live bed. It might be worth trying to contact him via PM or email. @Reef Maniac Might inspire him to become active again as well. Hopefully.
     
    Last edited by a moderator: 26 Nov 2015
Recent Posts

Loading...
Similar Threads - Plenum Plenum Plenum Forum Date
SSB vs DSB vs BB vs PLENUM Biological/Natural Filtration and Deep Sand Beds 27 Dec 2010
Q. on Plenum with DSB Biological/Natural Filtration and Deep Sand Beds 12 Jun 2009