Jaubert Plenum

[+Grog]

I'm adding Jaubert Plenum to the bottom of my sump/fuge in my 145g build with an approximately 6" deep sand bed.

Plan to use PVC pipe for the frame and support and zip ties to attach the membrane but wondering what others have successfully used for their plenum? I do kind of like the idea of reusing the base portion of an old undergravel filter as the plenum.

Seems that some folks use a secondary barrier about midway through the sand bed to keep sand stirring critters from disturbing the deepest part of the sand. Anyone here using a secondary barrier? If so,what are you using here? Same as above or a different material?

Grog

[Planeden]

If you are interested, I have a book that talks about reversing the plenum where the water blows up through the sand that prevents the waste from collecting under the sandbed. I don't remember which book it's in, but I can find it if you want.

You may know, Patrick has a plenum system.

[+Grog]

Yes, I'm aware he has one, he and I had discussions about it when I went over my design with him a month or two ago. Hoping to bring the discussion here so information and techniques can be shared.

I've done quite a bit of reading on the topic and I'm sold on using this method. Leaning towards PVC frame, egg crate on top, covered by nylon screen, ziptied and cemented together.

Thinking the secondary layer of fabric may be unnecessary.

[bige]

I'd like to follow along. I've read about these and seen them in person and am still a little lost.

[Planeden]

I think the only difference in design between the blow version and suck version is where the air goes. In the blow version the air stone goes in the plenum lowering the pressure there to move water out of the tube. For the blow version the air is released under the sand' lowering the pressure there and bringing water into the tube.

I'm not trying to change your mind, just sharing the info .

I don't remember what I read about the barrier, so I can't speak to that.

[subsea]

The secondary layer is unnecessary.

A DSB with coarse aragonite substrate is a powerful nitrate exporter. The coarse substrate extends the oxygen gradient over a larger volume, which means more bacteria per unit volume. Both nitrifying and de-nitrifying bacteria live in this substrate, which I like to call the faculative zone. Faculative bacteria are 100 fold more productive than sulfide bacteria at converting NO4 to free nitrogen gas which is a nutrient export mechanism.

Bring on the bugs,

Patrick

[+Grog]

Thanks Patrick.

Yes, bring on the bugs. Once I return from Alaska, I'll be ready to get this tank cycling. I don't want to leave it for 10 days in the hands of a non-reefer house sitter while it is coming online. So, I'll get started after, and enjoy my vacation.

I'll get parts at Lowes after work tonight.

Planeden,

My intent is to not install any air/water moving mechanism under. It will be a layer between the DSB and the bottom of the sump, no pump to circulate the water out from under the plenum. Cross section like this:

~~~~~~~~~ <--Sand

-------------- <--Nylon Mesh

-------------- <--Egg Crate

O O O <--PVC Frame

-------------- <--Bottom of Sump

Bige,

Here is a good article, very similar to the information found in Reefkeeping Vol III. http://www.advancedaquarist.com/2002/9/aafeature

-Grog

[Planeden]

Planeden,

My intent is to not install any air/water moving mechanism under. It will be a layer between the DSB and the bottom of the sump, no pump to circulate the water out from under the plenum. Cross section like this:

~~~~~~~~~ <--Sand

-------------- <--Nylon Mesh

-------------- <--Egg Crate

O O O <--PVC Frame

-------------- <--Bottom of Sump

-Grog

Sorry. You're right. I'm an idiot and was thinking of something else. Let's just forget this ever happened .

[bige]

So it's the air in the space on the bottom that makes this efficient? What if no space on the bottom? But dsb aragonite?

[subsea]

Se quote name="bige" post="215432" timestamp="1375929203"]So it's the air in the space on the bottom that makes this efficient? What if no space on the bottom? But dsb aragonite?

I am not a scientist.

Amongst other things, I am an operations engineer. I will describe what I have used for twenty years with a Jaubert Plenum.

First, there is no air in the plenum. It is a void of water. Consider redox values as an evaluation tool. From the top of substrate, at the water/substrate interface both redox, pH, and oxygen are at there highest. As water migrates down thru the substrate, oxygen, redox and pH decrease. As the oxygen decreases, nitrifying bacteria give way to de-nitrifying bacteria. This is complete nutrient export with free nitrogen gas exported from the water. As oxygen is depleted in the depths of this sandbed, faculative bacteria give way to sulfide bacteria. Below the sulfide anerobic bacteria is the void of the plenum which is at a higher redox value than the anerobic zone. In effect, the anerobic bacteria are sandwiched in between higher redox value zones.

Alkalinity buffering and dosing are a freebie with the use of arogonite substrate.

Laissez a bonne temps roulee,

Patrick

[subsea]

Before people ask, how does the water move down thru the substrate, I will answer "Read Julian Sprung and Charles Delbrick's chapter on the Jaubert Plenum. After more than 20 years of documenting results of aquariums using Jaubert Plenum, both of these scientist and authors agree that the Jaubert Plenum produces superior results than DSB alone. I know it works and I will continue to use it. With any DSB method, janitors need to be appropriate. When I use Florida Crushed Coral at 2mm-5mm, I use serpent stars and bristle worms at the top. Combined with pods, these janitors do a complete job at the surface. The rest of the sandbed is populated by bacteria.

No discussion of DSB methods would be complete without mentioning the oxygen consumed by the sandbed. Within one hour, oxygen depletion will kill fish. Automatic back up systems should be standard on a large reef tank investment of time and money.

Patrick

[(Bio)³]

So how does the water move if you don't put an air stone in it?

[subsea]

Diffusion. Electrical chemistry due to changing redox value. Gravitational pull from Saturn.

[victoly]

You sure it isn't Uranus?








c'mon now, there has never been a better setup in the history of humanity.

[Timfish]

. . . What if no space on the bottom? . . .

This, like everything else in this hobby, is argued! If you come across any of Dr. Toonen's stuff he argues against having an empty chamber/area/plenum under the DSB. For further minutae Dr. Shimek champions very small grain size, I think it's less than .5mm, while Dr. Jaubert argues for roughly a 2mm grain size.

@ Victoly: You're absolutely right.

[+Grog]

Here is my quick build tonight.

PVC spacers,

Cut eggcrate

Glued to eggcrate, Used CPVC pipe and CPVC cement because that is what I had, not because CPVC was necessary.....

Zip tied nylon screen and set into the sump. Will dump sand on top. (zip tied on ends just to hold together. left flaps on the side to keep sand from sliding in to it from the edge.

[bige]

Looks good. Look forward to it being wet.

[+Grog]

That makes two of us!

Will have to wait till I return from Alaska on the 23rd though!