Q. on Plenum with DSB

Discussion in 'Biological/Natural Filtration and Deep Sand Beds' started by Pads, 12 Jun 2009.

  1. Pads

    Pads

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston
    Hi Guys, Could anyone give some assistance with this problem. I've used an old 2 ft tank
    as my sump for my 3ft tank. Now the DSB compartment is 300(l) x 300(b) x 180(h)
    Can I have a plenum of 20mm at the bottom and then the DSB or should I use the full height available for the sand. Any help would be greatly received.
     
  2. AdS Guest




    to hide all adverts.
  3. inflames

    inflames

    Joined:
    29 Oct 2008
    Posts:
    923
    Likes Received:
    9
    Location:
    Randparkridge (Johannesburg)
    Hi Pads,

    I personally have a plenum in my sump, but my plenum is 5cm of the floor and then has 15cm of sand above that and I still have space for about 4cm to 5cm of extra sand to be added without sacrificy water flow over my Plenum/DSB. I initially did the measurments when building the divisions for the sump and made it higher than usual. With your question I would say just go for a DSB only. Dont worry to much about the plenum as from what I have gathered is they are almost OLD SCHOOL?!?! Just make sure that the water flow is not to high or to low over the DSB and you couldeven get a hermit crab to enjoy sifting through the sand in the sump! Dont try grow cheato ( I learnt the hard way!!) in the same compartment with your hermit!!;)

    Hope this help!!
     
  4. Pads

    Pads Thread Starter

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston
    Cheers;) I wasn't sure about the most optimum sand depth. Do you know how long your sump/DSB took to have a noticeable effect on your water parameters? I'm going away and need to get this thing running to help keep it stable.
     
  5. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,161
    Likes Received:
    1,230
    Location:
    Centurion
    DSB should be 15 deep,
    That gives you just 2 for water depth and 1 cm before flooding

    Rather start with a deeper option. Just a suggestion. Your tank is too shallow fot me.
     
  6. sihaya

    sihaya

    Joined:
    6 May 2007
    Posts:
    1,493
    Likes Received:
    35
    Location:
    USA
    The sand bed needs to be about 100mm. You don't have to have a whole lot of water above the sand bed, but I'd feel uncomfortable with much less than 80mm above the sand bed...
     
  7. jacquesb

    jacquesb Retired Moderator

    Joined:
    29 May 2007
    Posts:
    17,868
    Likes Received:
    69
    Location:
    Cape Town
    Sorry Sara for the contradiction - BUT - I would MUCH rather have a sand bed of 120mm to 150mm to be safe. I would see 100mm to be the ABSOLUTE minimum of a DSB.........
     
  8. sihaya

    sihaya

    Joined:
    6 May 2007
    Posts:
    1,493
    Likes Received:
    35
    Location:
    USA
    Oh, yes, I agree. 100mm is the minimum... and up to about 160mm is best (thus I agree, 120 to 150mm is likely ideal). But just to say this again (for those who still haven't heard it)... you won't get much, if any, more utility out of the sand bed past about 160mm. The "deeper the better" idea is a common misunderstanding... the functionality of a DSB occurs within a relatively narrow range of depth.
     
  9. jacquesb

    jacquesb Retired Moderator

    Joined:
    29 May 2007
    Posts:
    17,868
    Likes Received:
    69
    Location:
    Cape Town
    Sara - I believe STRONGLY that even though depth is very important, that total square metre'age of the UPPER surface of the DSB, is FAR more important, than whether you go 150 or 200mm....... The bigger the square metres of a DSB, he better!
     
  10. sihaya

    sihaya

    Joined:
    6 May 2007
    Posts:
    1,493
    Likes Received:
    35
    Location:
    USA
    You're preaching to the choir here my friend! :)
     
  11. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Guys (and that includes you, Sara :thumbup:) to have any meaning, we should link the depth of the DLSB to the particle size of the DLSB. One can very successfully keep a DLSB of only (say) 80mm deep IF one use a very fine (near mud...) sized sand - on the other hand, with a course sand one might need to make the DLSB a minimum of (say) 250mm thick to obtain the same results.

    A lot of research has gone into determining the right particle size, and optimum depth, of a DLSB. I believe in the method recommended by Dr. Toonen (Biogeek) some years ago: Initially make the bed between 100mm and 150mm thick (depending on particle size), and let the tank run for a month or two. If no black zones develop on the bottom of the sand bed (without plenum!), increase the depth by 25mm and let it settle for another month or so. Continue with this increase until some smallish black areas form in the bottom of the sand. This would then be the optimum depth.

    Here are some links:

    How Sandbeds REALLY Work by Ronald L. Shimek, Ph.D. - Reefkeeping.com
    Applications of Sand in Reef Aquariums: Theory and Practice by Eric Borneman - Reefkeeping.com
    Seabay Article- Are Plenums Obsolete? Another Viewpoint Part 1 by Dr. Rob Toonen

    Hennie
     
    Last edited: 13 Jun 2009
  12. jacquesb

    jacquesb Retired Moderator

    Joined:
    29 May 2007
    Posts:
    17,868
    Likes Received:
    69
    Location:
    Cape Town
    Thanks Hennie - I was JUST thinking about that, while I was reading the other posts - until I got to YOUR post! - You just confirmed what I was thinking!
     
  13. sihaya

    sihaya

    Joined:
    6 May 2007
    Posts:
    1,493
    Likes Received:
    35
    Location:
    USA
    Ditto

    And thanks Hennie for posting that Toonen article link. I've been looking for that for ages! Much of what I say (or try to explain) comes from that article...
     
  14. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
  15. Pads

    Pads Thread Starter

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston
    Hi Sara, Jaques and Hennie, I've read what you've all got to say and, I'd love to build a larger tank and sump but at the mo I don't have the space. Another thing is that I'm about to tie the knot and the fiance will kill if I spend anymore money and excess time on the tank I might lose my family jewels. So for now I converted an old 2 ft tank into a sump to assist with the stability until after the marriage and honeymoon etc.

    I was not exactly sure about DSB depth and if I had one of 10 or 12cm if that would be too little and of no benefit. The DSB will most likely be 15cm with 3cm water in line with glass baffle then another 1cm free flowing water over the DSB.

    What would you say is an estimated time to see noticeable difference water quality with the sump/DSB operating?

    Thx again for the help ;)
     
  16. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Well, what can I say... RUN while you still have the time :whistling:

    If you have a high reading of nitrates then you should see if fall within about 4-6 weeks. The other benefit of a DLSB (adding live food into your system) should start even sooner, but might take slightly longer to fully develop, depending on the initial amount of "life" you introduce into the sand. I would recommend that you obtain a few handfuls of sand from as many fellow reefers as possible, and place one or two pieces of uncured live rock in the sump to boost the variety of life forms. If the system is very new then it would benefit the DLSB if you very sparingly feed the DLSB critters with small amounts of food (sinking food pellets or finely grated pieces of frozen shrimp, prawn or fish) until the display tank can take over that function.

    Hennie
     
  17. Pads

    Pads Thread Starter

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston
    If you have a high reading of nitrates then you should see if fall within about 4-6 weeks. The other benefit of a DLSB (adding live food into your system) should start even sooner, but might take slightly longer to fully develop, depending on the initial amount of "life" you introduce into the sand. I would recommend that you obtain a few handfuls of sand from as many fellow reefers as possible, and place one or two pieces of uncured live rock in the sump to boost the variety of life forms. If the system is very new then it would benefit the DLSB if you very sparingly feed the DLSB critters with small amounts of food (sinking food pellets or finely grated pieces of frozen shrimp, prawn or fish) until the display tank can take over that function.

    Hennie[/quote]

    Super! Thx again Hennie ;)
     
  18. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,161
    Likes Received:
    1,230
    Location:
    Centurion
    Just another suggestion
    If you do nat have the space
    and
    You do not have the time
    and
    You have got nitrate and phosphate problems

    Why not install a simple scrubber above the 2 foot tank?
    Can even have it above the DSB, I got it like that. And it works.
     
  19. Pads

    Pads Thread Starter

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston

    Hey Riaan, I don't really have nitrate/ phos problems but I wanted the sump to help stabilise the tank, I'm currently doing 10% water changes every week and I'm getting a little bored of the routine. I'm hoping with the sump I only have to do a water change once a month. I've tried the scrubber idea before but with the evaporation it quickly got sidelined and I don't think the flow on it was enough so I didn't notice any changes. Maybe I'll have another look at the system and see if I can intergrate it again.
     
  20. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,161
    Likes Received:
    1,230
    Location:
    Centurion
    If you do not do 10% water changes per week, you have to do dosing of stuff.

    So either at least 10% or a lot of extra money to dose minerals..

    Ask the experts. This is the advice I got from Louis at Idol Marine. Especially on a softy tank 10% per week is enough, no need to dose anything in particular.

    Yes top up is a problem with an open scrubber. Then again that cools the tank down and I do not need a chiller... So it is a bit of this and a bit of that. You will end up with some routine...:)
     
  21. Pads

    Pads Thread Starter

    Joined:
    18 Aug 2008
    Posts:
    689
    Likes Received:
    4
    Location:
    Joburg, Bryanston
    Ja a fair call I guess. The hastle is that when I'm away the fiance will not be caught dead doing a water change for me. At least you can teach dogs tricks but try teach a human to do a water change and...... eish:whistling: She just doesn't share my passion to the same extent
     
Recent Posts

Loading...
Similar Threads - Plenum Forum Date
Plenum - To Plenum or Not to Plenum (This is the question) Biological/Natural Filtration and Deep Sand Beds 26 Oct 2012
SSB vs DSB vs BB vs PLENUM Biological/Natural Filtration and Deep Sand Beds 27 Dec 2010