Plenum system in live sand? anyone tried this?

[SPC]

Posted by Fishfarmer:

Yes, Bob Goemans recommends vacuuming areas where detritus collects once a month and every two to three months vacuum the entire sandbed, but only going down 1/2 to 1 inch. Bob Goemans also states that Dr. Jaubert recommends to leave 75% of the sandbed unobstructed by rock.

-I guess my question would be if we can get the same results from both methods, then why would I even consider having to meet the above requirements? Right now with my DSB I have zero maintenance and am able to employ a wide variety of animals to do the work for me. I obviously can't keep these animals in a plenum system because of:
1. The grain size of the substrate does not meet their needs.
2. Many will be siphoned out and destroyed.
Steve

 

[ChrisRD]

-I guess my question would be if we can get the same results from both methods, then why would I even consider having to meet the above requirements?

My feelings, exactly

 

[Lady Godiva]

This is a very informative thread. I've increased my knowledge and understanding of both DSB's and plenums about 80% just reading through it.

One thing I am confused about however, and pardon me if I've simply missed it somewhere in the information provided, is that it seems as though we can get to the same results, regardless of which method is chosen. The only difference seems to be the structure of the process that is being used.

Am I missing something? Basically, I am asking, if we were to develop a list of postitives and negatives associated with each method, would any of the items listed have anything to do with the actual performance of either method? Can it be said emphircially, that there are issues associated with either method, that cause harm or potential harm to a system, or that potentially don't provide adequate filtering functions necessary to provide for proper nutrient export?

Karen

 

[Anonymous]

i'm still just trying to figure out how a static body of water can transport oxygen to the underside of a sandbed.... :roll:

 

[camp6]

im a big time newbie to this but ive read the "live sand secrets" and to sum up in one sentece its says that by adding the plenum you are able to utilize an entire 4" sand bed to help handle bioload. This theoretically allows one to have more fish in the same amount of tank. By not using a plenum it doesnt matter how deep your sand bed is, 2" or 2', only the top 1" or so actually is useful to handle bioload. it is also very specific about how the plenum should be built, no light underneath, etc. I think i will attempt this on my next tank.

 

[ChrisRD]

Vitz:

I think I have the answer...

It can't and doesn't

 

[ChrisRD]

By not using a plenum it doesnt matter how deep your sand bed is, 2" or 2', only the top 1" or so actually is useful to handle bioload.

This statement is false.

Check out this link for more information about DSBs.

 

[Nelliereefster]

Just want to say GOTCHA!!!

Out of the darkness, you all came, armed and vociferous, and a great case you've made. I will rethink my plenum ideas. Maybe I'll try to do the unthinkable, and gather some new data over time.

Smashing thread. Well done to all defending their position and offering alternative views... 8) 8) 8) 8) 8) 8) 8) 8) 8) 8) 8)

 

[Lady Godiva]

i'm still just trying to figure out how a static body of water can transport oxygen to the underside of a sandbed.... :roll:

Vitz:

I think I have the answer...

It can't and doesn't

Not to beat a dead horse (see sump :lol: ) and, I see the post is wrapped up by Nelliereefsterm, but there are a couple details that escape me in the logic.

I am not interested in setting up a phlenum and am convinced from the 4-5 Shimek articles I've read today that DSB is the way to go but, I am interested in understanding the theory of a phlenum.
I'm still a bit confused on the theory of how it is supposed to work. As I understand it, the purpose of the stagnant water under the sand is to maintain the anoxicity of the substrate above. Is that correct? If so, how exactly does the stagnant water area supposedly do that?

Wolfman, you said above that it can't and doesn't. That being the case, what DOES that stagnant water area offer to the process of nutrient export, or, is THAT what the debate is all about?

Thanks in advance for indulging me in my endless, on-going quest for understanding :lol:

Karen

 

[ChrisRD]

Karen:

This link contains an article with a basic summary of how a plenum works and should be setup.

 

[Biogeek]

I wrote a sandbed series for FAMA a couple of years ago titled "Are plenums obsolete?" that has recently been put onto the web by the folks at SEABay (Part 1 and Part 2). In that article I try to explain a little bit of sediment ecology and why a DSB should actually outperform a plenum in theory. Like Ron Shimek, I disagree with many of Bob's assertions about the dangers of DSBs and the benefits of plenums. In fact, I am currently running a number of experiments to directly compare the relative efficiencies of these approaches for my talk at IMAC next year (which should be especially interesting with Bob Goemans and I both speaking about this topic).

As for a sandbed being unstable over the time-scale of years, I set up my first DSB tank in 1985 (with silica-based quartz sand, because there was no fine aragonite source at the time), and only took it down to move this past Christmas (here is the tank after 16yrs on a DSB) without having any problems of instability or any "DSB crash"...

Rob

 

[D.W.L.]

Sooooooooo, Rob, no OTS in that old tank.

 

[ChrisRD]

Rob:

Thanks for adding some credentials to this thread!! Thanks for the info - another link for the favorites list!


Karen:

Here's a thread where the pros/cons of DSBs/Plenums were argued before on RDO. The theory of what purpose the space under the plenum serves was discussed here. Rob's articles are a much more thorough explanation of how/why natural sediment systems work.

 

[Anonymous]

Rob-thanx, as well 8)

fwiw-i've seen people lose continual red cyano problems after switching from plenum to dsb-also in fo setups.

(your article was exactly what i was looking for-re:zone specifics in the beds! 8) )

btw-wasn't the jaubert system originally designed for large volume/low load setups?my memory (hazy)seems to recall it being mentioned in connection w/the monaco aquarium in 'the marine aquarium in theory and practice'(?)...

 

[Lady Godiva]

Wolfy,
More homework - thanks! Seriously, I appreciate you providing the threads. :wink:

All, thanks for a sharing your viewpoints.

Karen

 

[ReefMon]

Be sure to ask Tom at Marine Scene about the plenum tank that totaly crashed overnight, I do think he has changed his position on Jaubert Plenum systems.

Having been to the Monaco Aquarium, I found it interesting that the substrate consists of very corse crushed coral that was IMO completely devoid of life, plus the fact that they are "open systems" with a constant supply of filtered NSW from the Mediterranean. How these open systems compares to our closed systems is beyond me.

ReefLion & Nelliereefster...
Any frags for sale/trade out there????

Check out WAMAS for local frag trading & more....

 

[ReefLion]

How did I miss that quote asking for frags or trade? I still can't find it. Anyway, I had to break down and unload everything in my DC tank, and I'm starting from scratch so I'm looking for frags at this point. =)

 

[dleiter65]

I have been running a plenum for about 1 and a half yrs. I like it . But I did find out that you have to filter the sand about every 3 months, for me it works pretty well. I'm kinda afraid of always messing with it but, if it works ! What the the heck!