The Sand Bed Debate is over !! the plenum is dead

[Mitch#3]

From the most recient Advanced Aquarist comes a great study by Rob Toonen AKA Biogeek, formerly of Edmonton Alberta now on an island

Feature Article: An Experimental Comparison of Sandbed and Plenum-Based Systems. Part 1: Controlled lab dosing experiments

Background and Introduction:
Plenum-based systems gained widespread acceptance after Dr. Jean Jaubert worked with the Monaco Aquarium in transporting a complete live portion of a coral reef from the Red Sea for display at the Aquarium. Dr. Jaubert worked extensively with naturally-collected coral substrates to enhance captive biological filtration in captive aquaria, and was granted a French patent for the plenum design in the late 1980s followed by a US patent the early 1990s. Based largely on the success of the Monaco Aquarium's "Microcean" display, this plenum-based aquarium design has become one of the primary design methods used by public aquaria around the world, and for nearly a decade was almost equally popular among hobbyists maintaining home aquaria.
However, in the past several years, the "deep sandbed" design has largely supplanted plenum-based systems among US hobbyists. The reliance on a thick bed of carbonate sediments is essentially the same as that of plenum-based system, but the utility of the void space beneath those sediments has been vigorously questioned. Advocates of deep sandbeds argue that it is the sediment itself and not to presence of a void space beneath those sediments that perform the nutrient processing capacity (e.g., Toonen 2000a, 2000b). There have been numerous articles and books written in the aquarium hobby about the advantages and disadvantages of designs for each of these two recirculating systems (e.g., Adey & Loveland 1991, Tullock 1997, Auger 1999, Goemans 1999, Shimek 2001, Hovanec 2003, Delbeek & Sprung In press). There remains considerable debate about the most efficient design of a sediment bed for processing nutrients in a recirculating system, but to date these arguments have been based almost entirely on personal opinion and anecdotal evidence.

For the ballance of the article http://www.advancedaquarist.com/2005/6/aafeature

Part one of two

If you cant wait, and I couldn't the original study was published in Aquaculture

Cheers
MitchMc

[Doug]

He,s been bashing plenums for years. See Fama a couple years ago. Most of the dsb followers, have a strong dislike for plenums.

[Mitch#3]

Originally Posted by Doug

He,s been bashing plenums for years. See Fama a couple years ago. Most of the dsb followers, have a strong dislike for plenums.

Interestingly enough his findings indicate that not only is there no difference between plenums and non plenum systems but

there is no difference between deep vs shallow beds,

and outside of buffering little difference between coarse and fine sand

I find this to be a strange position for a dsb follower to take

In the past he had advocated deep fine sandbeds (1) the study shoots that all to hell, good on him for doing a real scientific study and even better on him for reporting the results to the community when he has proven his previous opinion wrong

Cheers
Mitch

(1) he would say mixed but a mix of generally fine sands

[Doug]

Hi Mitch,
Yes, it was good to see the lean towards shallow beds also. Actually Rob has been the most moderate of the sand "gurus".

The problem I have had, is that it was as hard to argue with them as it is with some of the barebottom fanatics now.

The same could be said for Gamble & Goemans advocating the plenums. At least the plenum systems were brought forward by the Monaco Aquarium and Dr. Jaubert.

Another fact is, when you search all the threads on the various sites, it seems besides Robs often mentioned tank in Edmonton, there are more longer running plenum systems than dsb systems. I assume thats the ones that are run correctly, with little live rock blocking the gravels access to the water and gives good gravel cleaning ability.

However, it is an interesting article and at least good to see them running more experiments on various systems.

Question, Did I miss it or why did Rob not run the same test on a plenum system?

And why such a short time period on the experiments?

And where is the long awaited results from the long term experiments on plenums, run by Delbeek at the Waikiki Aquarium?

[Mitch#3]

Originally Posted by Doug

Hi Mitch,

Hi Doug

Originally Posted by Doug

Rob has been the most moderate of the sand "gurus".......The problem I have had, is that it was as hard to argue with them as it is with some of the barebottom fanatics now.

Yes it is a problem and one without a solution to quote one of my favorite statesmen

"A fanatic is one who can't change his mind and won't change the subject"--Winston Churchill

The truth is set out in my signature

Originally Posted by Doug

The same could be said for Gamble & Goemans advocating the plenums. At least the plenum systems were brought forward by the Monaco Aquarium and Dr. Jaubert.

Fanatics on opposite ends of a debate
are more similar than slightly opposed moderates

Originally Posted by Doug

However, it is an interesting article and at least good to see them running more experiments on various systems.

yes it is nice to see a scientific eye backed up with a verifiable testing protocal

Originally Posted by Doug

Question, Did I miss it or why did Rob not run the same test on a plenum system?

Originally Posted by Robs Report

We set up a factorial design experiment with three replicate nano-tanks (27 cm long x 17 cm wide x 30 cm high) for each factor: with or without plenum, deep or shallow, and coarse or fine sediments for a total of 24 experimental aquaria (Fig. 1a,b).

All tank combinations were run for both plenum And non-plenum systems

Originally Posted by Doug

And why such a short time period on the experiments?

Considerable recourses were required to run the experiment for as long as it ran

Also

Originally Posted by Bio Geek the Reef God

Time-series of ammonia, nitrite and nitrate concentrations in aquaria showed little difference among treatments (Figs. 4-6). After the initial 21d, there were no significant differences among ammonia, nitrite, nitrate, pH or salinity measured for any treatments through the end of the experiment

If there was no significant change for 90 days ( the experiment ran for 121d) one would have to come up with a really good reason /idea to explain how or why a change would suddenly and spontaneously occur after all systems had reached a steady state/equilibrium for three months

Rob would have run it for years but resourses are limited
I think its cool he managed to work in some tanks with live critters

[Mitch#3]

Helllo

I set up my new tank after I had read the article, kept the deep fine sand bed in both the display tank and the sump, seems to make a marginal difference in buffering and critter survival

Does any one care

Did anyone even read the article

Will this change your next tanks set up


SH*T time for a beer

[StirCrazy]

Originally Posted by Mitch#3

Helllo

I set up my new tank after I had read the article, kept the deep fine sand bed in both the display tank and the sump, seems to make a marginal difference in buffering and critter survival

Does any one care

Did anyone even read the article

Will this change your next tanks set up


SH*T time for a beer

well considering that it is nothing new information wise and that it just confirms what a lot have people have been saying for the last two years I don't see the need to say much, of as for buffering, that is a non issue also, 4 years ago there was a study between a tank with Sugar sand, one with crushed coral and one with a bare bottom. they were left to deplete naturally to see which one had a Ca crash first, well after 3 months the BB crashed, then a week later the crushed coral crashed then a few days later the sugar sand.. so not really a concern as to which is better for buffering.

My views on using a sand bed for denitrifacation now have radically changed, if you read my beginning posts a few years ago I was a fanatic for sand beds, now I look at them as a fix for pour set up and husbandry. if you create your tank setup right (as in equipment) and clean crud out once a month (or so ) you won't need the detritus break down of a sand bed as it will all be taken care of. the rock in most tanks do more than enuf of a job for handling nitrates.

a situation where I would recommend a sand bed is in a under skimmed or skimmer less tank.

Steve

[Mitch#3]

Originally Posted by StirCrazy

well considering that it is nothing new information wise and that it just confirms what a lot have people have been saying for the last two years I don't see the need to say much,
Steve

I am not sure that I agree with you 100%
While it may confirm what "a lot" of people have been saying
It offers some scientific basis to justify their position. Further it
Fly’s in the face of what most hobbyists “know” to be true.

There are still a lot of people who argue passionately about the depth composition ect of the sand bed. In some forums the bare assed vs sandbed debate rages bitterly....

Originally Posted by StirCrazy

...... a4 years ago there was a study between a tank with Sugar sand, one with crushed coral and one with a bare bottom. they were left to deplete naturally to see which one had a Ca crash first, well after 3 months the BB crashed, then a week later the crushed coral crashed then a few days later the sugar sand.. so not really a concern as to which is better for buffering.

You wouldn't have a url or cite for this would you? It sounds kind of interesting.

Originally Posted by StirCrazy

............. you won't need the detritus break down of a sand bed as it will all be taken care of. the rock in most tanks do more than enuf of a job for handling nitrates.
Steve

The rocks may not be as significant as the current wisdom suggests

In the live animal trials about 1lb/gal of live rock was added to the systems

After adjusting the final nitrate levels [in terms of the difference between the lower nitrogen input levels in the live (with rock) systems and the higher nitrogen input levels of the dosed (without rock) tanks] it does not appear that the rocks made a statistically valid difference in final nitrate levels.

In terms of your comment

Originally Posted by StirCrazy

My views on using a sand bed for denitrifacation now have radically changed, ... I was a fanatic for sand beds,..... if you create your tank setup right (as in equipment) and clean crud out once a month (or so ) you won't need the detritus break down of a sand bed .......
Steve

I could not agree more

I set up my new tank about a month ago and rather than worrying about limiting bio load and nitrate (food) input to the tank I am using a Sulfur limestone Autotrophic denitrifer ( for nitrate removal) and Ferris oxide hydroxide (for phos removal).
Feed, let it break down, then remove it

only had critters for a week SO WE WILL HAVE TO SEE