Jaubert Plenum

[Cougra]

Is there any determined surfacearea to bioload ratio? How would we be able to determine the size this remote plenum needs to be?

and in a remote location we allow fo no light, no light means no algae, which means the phosphate stays in animal form and can be exported via the suction (in animal form I am talking bacteria only).

I think I missunderstood this previously, I know that you needed to minimalize the light in the lower layers, but I for some reason I didn't realise that we weren't adding any sort of light to the plenum. This would make the system much more economical since you don't need additional electricity to run it and replacement bulbs.

How deep does the water ON TOP of the plenum need to be? would you be able to get away withmerely one or two inches of water to basically cover just the plenums substrate material or does it need to be deeper? This would also allow you to be able to stack a couple systems ontop of one leaving a couple inches head room for access and airflow, so you could utilize a minimal amount of space for additional surface area. It would also keep the water well oxygenated since there is a larger surface area to volume ratio.

 

[ScottT1980]

How deep does the water ON TOP of the plenum need to be? would you be able to get away withmerely one or two inches of water to basically cover just the plenums substrate material or does it need to be deeper? This would also allow you to be able to stack a couple systems ontop of one leaving a couple inches head room for access and airflow, so you could utilize a minimal amount of space for additional surface area. It would also keep the water well oxygenated since there is a larger surface area to volume ratio.

It seems to me that this would be even more efficient. If you are constantly running a "thin" layer of water over the plenum, it seems that filtration would occur more readily as opposed to a large volume of water, most of which will not come into immediate contact with the sandbed.

I think I missunderstood this previously, I know that you needed to minimalize the light in the lower layers, but I for some reason I didn't realise that we weren't adding any sort of light to the plenum. This would make the system much more economical since you don't need additional electricity to run it and replacement bulbs.

It seems to me that light would be needed for the system on top of the plenum. The reason being that the microinverts/nematodes/insert critter name here are dependent on some sort of photoperiod (but hey, I do the opposite keeping ym fuge lite 24/7 so perhaps the opposite can be done, I just know many animals, even the lower ones, have metabolic cycles dependent on photoperiod). I could easily be wrong, just a thought. As for light to the plenum, that is very easy to handle with or without light on top by just ensuring sand surrounds the entire thing...

Sorry, I am sort of in and out of this thread so I forget what has already been mentioned. Just some thoughts...

I really like the low water depth plenum idea though, surious as to what others may think.

Take er easy
Scott T.

 

[Curtswearing]

I have read of people who only run a couple of centimeters of water over the top of the substrate. This seems more efficient to me as well. Michelle your point about the oxygen is well taken. That possibly would have an impact on my concern with CO2 dropping the pH levels. What do you guys think?

Sorry I keep popping in at out at irregular times.....I want to know what is going on but I have a bunch of meetings today.

 

[Maxx]

Nick on the two plenum system, yes that can be done and can be done just as you discribe it. Where I am leaning is to try to bring about a system where total reakdown is not needed. We have lined out most of the problems that sand substraights have and I think have worked past them. if we excersize the proper setup and miantence cant we gat past the breakdown, if not wat are you seeing that requires it? tell me what you think is going to cause the need for a complete redo.

Mike,
Total breakdown was meant as a last resort type dealie... I can see that gravel washing would more than sufice if done on a yearly basis. Otherwise I'm quite certain that the drain/pump system you mentioned, used in conjunction w/ vigorous stirring on occasion, would be more than enough. For the purposes of this system, I'm looking at the gravel washing as part of the maintenance to be done a regular basis, albeit with long intervals between. Or are you saying that this is uneccessary and potentially harmful to the population of the main/display tank over all?

This would also allow you to be able to stack a couple systems ontop of one leaving a couple inches head room for access and airflow, so you could utilize a minimal amount of space for additional surface area.

Okay granted I'm not the smartest guy here, (that house monkey thing is only partially a joke!) but are you suggesting multiple plenums in one container? how would this happen? Or are we discussing multiple shallow water plenums stacked up in seperate containers some where....like a rack or shelves er something? This makes more sense to me.

It seems to me that this would be even more efficient. If you are constantly running a "thin" layer of water over the plenum, it seems that filtration would occur more readily as opposed to a large volume of water, most of which will not come into immediate contact with the sandbed.

I thought that part of what made plenums work was the water pressure aspect which "pushed water through the plenum, (albeit slowly) and allowed denitrification to occur that way?

my concern with CO2 dropping the pH levels.

Umm I thought that the lower PH water was sposed to stay beneath the plenum? If thats the case, why are we worried about it? The only way Co2 would get free in the tank (from a plenum)and lower pH is if it was disturbed and the lower PH water was released. Taking the Plenum assembly (why not there's more than one in this discussion, we might as well call it an assembly...) off line to do any maintenance, and going w/ Mikes Plumbing /flush solution should adequately prevent that from happening. unless I've missed a post here somewhere and didnt catch the part where we need to be worried about low PH/ Co2 escaping into the aquarium from the plenum? As far as disturbing the plenum for cleaning and releasing the low ph/co2 monster, just have a plan for when you bring the plenum back on line w/ the rest of the system....run the effluent, (remote set up remember?) through a pitcher like Mike does for his Calcium reactor, (air stone inside pitcher off gasses the excess CO2), run it through your skimmer for a bit...
just some thoughts
Nick

 

[mojoreef]

Yep thats the concept folks. The thing we need to concider is contact time, the more the better, also plumbing straight form the tank or something close is also a concideration so we make sure the detritus hits the bed. So in what I was talking about, yep about 3 inches or so should be fine (it will also help with particle fall out). .
On the lighting I was thinking black no light. The bacteria required for processing does not require it. The lack of light breaks the phosphate cycle (organic wise) by not allowing the vegitation part of the cycle to be had. So instead of the bacteria dieing (releasing their bound phosphate) they die and the phosphate sinks with the carcusses instead of fueling the algae bloom. Then we give the whole thing a suck and life goes on.

"Its the solent Green facter" lol

Mike

 

[mojoreef]

Sorry Nick you beat me to the reply button
Nick I am not sure what the washing is supposed to do? I need some help on that??

I thought that part of what made plenums work was the water pressure aspect which "pushed water through the plenum, (albeit slowly) and allowed denitrification to occur that way?

Not to fast a flow, but pressure wise no. The nutrients and so on are migrated down by critter and bacterial action...and water flow.
Ok on the co2. If a power outage occurs the plenum (water, bed, not the plenum zone) will take a hit and co2 will be in the water, but also you whole tank will be experencing the same thing, but probibly a heck of a lot more. When the power goes out and the lights turn off, photosynthesis stop, oxygen from the surface stops, basically all oxygen input stops. But you critters (from fish to corals to worms) dont hold thier breathe, they keep sucking it up and exhaling co2. So where thier is a bioload expect co2 input.
On the plenum zone itself if you dont disturb it the water will not magically raise and pollute the system. If one times thier stirring with the sucking of the plenum, I also dont see any pollution coming from that source either. Plus you can just disconnect it from the main.

Mike

 

[Maxx]

Nick I am not sure what the washing is supposed to do? I need some help on that??

I was thinking detritus removal....crap sinks and w/ a system designed to pull stuff through it, your gonna get deep crap that needs to go....That was my line of thinking. Am I wrong?

If one times thier stirring with the sucking of the plenum, I also dont see any pollution coming from that source either. Plus you can just disconnect it from the main.

Uhhh...how is this different from gravel washing?

 

[mojoreef]

Ok thats why I asked. I was thinking you were talking about removing the particles and taking a hose to them or something. So I think we are on the same page.

mike

 

[Maxx]

Cool, I thought maybe I was being set up for the butt of an enormous joke....not that I mind, I just wanna hear the punch line...
Nick

 

[Cosmic]

Great thread you guys have going here. Sorry I'm so late in jumping in (seems to be my trend these days ), but I did have a few thoughts on this whole idea you have concieved.

Firstly, you mention using larger grain substrate for a more oxygenated flow through in the substrate. This is supposed to help with clogging mainly.
Now, with a fast flow rate going through your plenum area, what is going to make that piece of detritus decide to STAY in the plenum and not be returned to some other part of the system?

I don't know, but my concept of your plan is a modified undergravel filter, with a reversible powerhead to remove the buildup? Weren't we there about 10 years ago?

I haven't done any current research, but from what I recall, the reason the grains were the size and depths they were was to control the flow of water through your bed. Making use of larger particles means either a DEEPER bed than before, or a hit on denitrification.

Another problem I might foresee is the "drain" (whatever you opt to use) trying to suck more than the bed is going to allow through it. Remember, too much flow and we don't have any denitrification occuring, meaning less water (flow) through the bed also. Is it going to be able to pull 700 gph through it?? I think your suction problem might again pop up here, possibly.

I understand what you are trying to accomplish, but I'm not sure that I agree with the methods of achieving it. Flow rate is critical to the success of denitrification, and the way I see it now, you're just re-designing the UG filter.

Ok, you can take your shots now

Cos

 

[Maxx]

Now, with a fast flow rate going through your plenum area, what is going to make that piece of detritus decide to STAY in the plenum and not be returned to some other part of the system?

I agree...but who said anything about a fast flow?
We were just discussing the fast removal of detritus.If I missed something please tell me...
Nick

 

[Cosmic]

Oops,
Just re-read through this part quoted by Mike a few pages back:

the well airated upper zone has high energy and is kept areobic.

And somewhere between there and the end it got re-interpreted to a high flow in the WATER zone of the plenum filter. However, I still see some issues with an increased flow rate through the bed. You are going to have to fine tune very carefully the thickness of your bed Vs the grain size you plan to use. The larger size substrate is only going to make it harder to fine tune that flow to boot. While it's a great idea in order to solve the clogging issue, I'm not sure if it's going to work or not.
I'd be very interested in the results if someone does try it out.

I had an article around here discussing various methods of filtration, and how they compared as far as ammonia, nitrite, and nitrate handling capabalities over a duration of 6 months from being setup. If I recall, it actually took the plenum a bit longer than just a month before it could start handling nitrates effectively.

If we break this down a bit more, we can see that by flushing the bed and plenum area, we effectively wipe out the nitrate reducers. I think we can all agree on that. You are under the school of thought that this is ok, because the bed was rinsed thoroughly at the same time, and nothing is going to need broken down for some time. I can also agree with this. BUT...
Once it DOES have something to break down, it's going to have a LOT to break down, with no population levels of bacteria to handle that waste. it equates to cycling an aquarium the way I see it. Doing it off-line is better, but you are still going to have to get it cycled somehow before bringing it back online, IMO. Else you are looking at extra amounts of water changes, or something to help handle that transition.

Anyways, just wanted to throw out a few more thoughts from a different angle to stir things up a bit

Cos

 

[Maxx]

what we are doing is that we are using larger sediment in order to keep the substriaght fully oxygenated (by size of particle and water flow) this will not allow for the lowering of ph and thus no unbinding. The reaction zone or plenum zone is where all the lower ph and denitrifing occurs. you will get some melt down thier which will unbind the the sand and release its composition, but again with the larger particles and good flow it will quickly bind the phosphate back up because the water in the be is oxygenated and thus higher in ph

thats Mikes answer to this statement...

You are going to have to fine tune very carefully the thickness of your bed Vs the grain size you plan to use. The larger size substrate is only going to make it harder to fine tune that flow to boot. While it's a great idea in order to solve the clogging issue, I'm not sure if it's going to work or not.

by flushing the bed and plenum area, we effectively wipe out the nitrate reducers. I think we can all agree on that.

not quite....no wipe out should occur since the anerobic bacteria are facultative, (prefer to live in unoxygenated water due to a lack of competition from other bacteria) but they can live and function in oxygenated water. So you won't have to worry about building up a population again. In all honesty this info on the facultative bacteria is solely from Mike. Not that I doubt him, but I don't know what species of bacteria we are actually disscussing, and havent seen any scientific studies done to prove this, but I suspect, (hope) Mike does.
Nick

 

[mojoreef]

Hey Cos about time you jumped in. We will take all the opinions we can get. Let me see if I can answer a few of your concerns.

Firstly, you mention using larger grain substrate for a more oxygenated flow through in the substrate. This is supposed to help with clogging mainly.Now, with a fast flow rate going through your plenum area, what is going to make that piece of detritus decide to STAY in the plenum and not be returned to some other part of the system?

The concept wasnt designed to help with the clogging, but I do think it will. The main reason for it is to have and to maintain a good areobic zone. This is one of the downfalls of the finer particle beds. clogs raise the anaerobic zone. The rest is as Nick said.
Thier is no flow through the plenum zone, just once in a blue moon when we decide its time for a cleaning. Other then that the plenum water see no flow ever.

Making use of larger particles means either a DEEPER bed than before, or a hit on denitrification.

I dont think thier is going to be any real denitrification in the bed, maybe but not much. all thet is occuring in the plenum zone.

Mike

 

[NaH2O]

Holy Plenums, Batman! Boy, I don't read this thread all day and I get lost. Mike, is there anyway you would be able to write up what your current idea is....if you would set it up right now, then what would it be? This may also help those that would like to get in on the discussion, but get lost in all of the different ideas.

 

[mojoreef]

Oh yea Nikki make me do all the work, lol
Ok I think this is where we are at so far.
We have a remote plenum which has around an 1 1/2 plenum space covered by 2 layers of screening. On to of this we have around 3 inches of large particle argonite (about 2 to 3 times the size of CC). The remote unit will be running around 3 inches of water over it at a moderate to slow flow rate. With in the plenum space we have plumbed in pvc piping or installed a drain. Attached to the plumbing on the topside of the plenum is a PH.
OK concepts behind where we sit right now, starting on the top working down.
>Shallow water passing over the plenum will allow for an easier fallout of detritus (doesnt have the 2 feet of water to go through to land in the bed)
>Moderate to low flow. slightly quicker because we have gained from the depth of the water column, but slow enough to allow for contact time.
>Larger particle bed to allow better penetration of water into the bed. This will allow the majority to stay areobic ( a problem ther finer substraights have trouble doing), which accomidates a more viable critter population. Also the larger particles will allow for food partcles and bacterial flock not to glog the bed or create isolated anaerobic zones. Also accomediates the cleaning process.
>standard screening to stop critter migration into the plenum zone.
>plenum zone approx 1 to 1 1/2 deep.
> plenum run dark no lighting. Concept behind this is to break phosphate cycle by not allowing algae growth portion of the cycle.
> lower plenum is facilitated to be sucked/drain clean of end product and extra waste. This stops eventual build up of non nitrogen based products. Sucking or draining would by and annual?? event but could be customized based on bioload and food input.

I think that it so far????

Mike

 

[Maxx]

Soundsa great! What are we gonna put it in? Long and low sounds about right.....shallow trough? Seriously...
Nick

 

[RogueCorps]

Oh boy... Sorry to join in but now you're all going to have to explain things as if you're speaking to a 4 year old.

Whew... long thread. I'm just going to throw things out there as I try to remember them...

I don't think I'm understanding correctly. Is the plumbing and powerhead (or drain) connected to the plenum for the sole reason of occasionally removing the goo from beneath the plenum, or is it actually circulating all of the time sort of acting as a reverse UGF?

Is this system intended to function also as a denitrifier? If so then why minimize the anaerobic zone? It's anaerobic bacteria in the absence of oxygen that utilizes nitrates correct? From what I understand the active bacteria of the nitrogen cycle from old texts (nitrosomonous and nitrobacter) were not found to be present in a survey of 200 reef tanks across the U.S. The bacteria that was found present is Nitrospyra. Also its conversion from using oxygen to nitrates is not a sudden event, and that returning them to an aerobic environment quickly causes them to implode. Because of this I do believe a cycle and restart would occur durring cleaning or draining the plenum area.
*shameless use of smiley here*
:explode:

>Larger particle bed to allow better penetration of water into the bed. This will allow the majority to stay areobic ( a problem ther finer substraights have trouble doing), which accomidates a more viable critter population.

Hmm... "more" viable critter population? Meaning for biodiversisisty and production of natural zooplankton for the system? I'm not sure there. While it would provide habitat to greater depth for oxygen users, large CC sized particles just aren't the habitat for the huge biodiversity that is found in fine sand. While the CC bed would populate with polychaetes, nematodes, crustaceans, etc. I don't think it would create a "better" population. Counts of animals in large particles are far from numbers in fine substraight. There are also many polychaetes that do just fine in anaerobic conditions, basically holding their breath to feed beneath the RDL in sand systems.

I also question if an anaerobic zone is possible at all in this large of substraight. I guess if you're talking very large CC, then you may be getting denitrification from low oxygen cores in the CC, similiar to how live rock is able to process nitrates. Just thinking aloud. I think I'm going to regret this.

So this is a largely aerobic area? That's called bio-balls right? (Just kidding... just poking at Mike...)

-Rogue

 

[Flatlander]

Cos, just for the record, I dont agree with draining/flushing the plenum.

Mike,
On your last post regarding the building. Why two layers of screen? Would that not be more cloggable, { , dont ask me what that word is, }. Also I would use a minimum of 4 in. of gravel.

Rogue,
I dont believe the same diversity of critters in a Jaubert type bed, is the same nor required, as in a dsb. {my view of course}.

My thoughts on the larger gravel is for better water diffusion through-out the bed. I have never measured anything, but from my experiences with crushed coral, I believe it does become ozygen deficient, despite the larger size grains. Of course saying 5mm, is only as a very top end size. I believe the Geo Marine is more along 3mm to 4mm max. I do have some of the old crushed coral that is around 5mm though.

 

[Cosmic]

I also question if an anaerobic zone is possible at all in this large of substraight. I guess if you're talking very large CC, then you may be getting denitrification from low oxygen cores in the CC, similiar to how live rock is able to process nitrates. Just thinking aloud. I think I'm going to regret this.

This is what I was trying to get at with a faster flow-through rate of the bed. I understand denitrification is not happening IN the bed itself, but UNDER it. But allowing a larger grain in your bed opens up more water getting down there, and hence more oxygen. This is going to result in Less denitrification unless you can compensate for this in some fashion. Hence the deeper bed idea.

Remember, there are a lot of success AND failure stories when using plenums, just like any other style of filtration. The reason it fails usually is because the bed was improperly setup to allow too much diffussion down to the plenum area.

This subject has already been fine-tuned by Jaubert and the Monaco aquarium as far as grain sizes and bed depths are concerned. According to thier research, they already HAVE the optimal size substrate. Mojo, you yourself said we are trying to take what they did and make it work for us. This means compromise in order to achieve other benefits. The compromise in this case is more oxygen to the plenum area, and hence less denitrification than before.

On another note, these faster flow rates also raise pH levels slightly, meaning that the little elemental replenishment you were getting is now going to disappear. If the PO4 is being re-bound, why not the desirables too?

Doug,

Mike,
On your last post regarding the building. Why two layers of screen? Would that not be more cloggable, { , dont ask me what that word is, }. Also I would use a minimum of 4 in. of gravel.

I started out reading this thread thinking that 2 layers of screen would surely be beneficial. as it allows a safe barrier when siphoning or stirring the gravel on the surface. This top layer would be placed approximately where denitrification starts to take place, or even slightly above to ensure oxygen saturation doesn't occur. Sure it has a better chance of clogging, but at the same time, it helps keep the clogs up in the top where you could also vacum during your normal water changes. This in return would go to extending the life of the bed.

I'm not FULLY against trying to find a way to clean the plenum, but I'm not sure draining it is the best idea. I just can't possibly see how it's not going to affect the tank in some nasty way.

Another idea to achieve this, WITHOUT destroying the plenum's functionality might be to have a closed loop attached to it, with a micron filter or something in-line. Open the ball valves, turn on the pump (a magnum 350 would be ideal IMO), and push whatever water you suck out right back in, but with sediment removed. The only problem here is trying to make sure the water in the magnum is fully anaerobic before turning it on, right?

I'm still not even convinced that the Magnum closed loop will work, but I think it has a bit more plausability than the draining method, which would totally destroy your tanks filtration capabilities for some time. We need to find a less-destructful way of achieving the cleaning so that our occupants don't notice the "bump" in the system.

Just my 2 pennies,
Cos