Jaubert Plenum

[Flatlander]

Most plenum failures I know of, were not attributed to the gravel being to large.

More the other and to fine was used, clogging down the system. Remember most of the older methods, used courser on the bottom and finer on the top, something not practiced by Jaubert. Also the usual failures because of the plenum design itself and in other cases, the bed being smothered by rock.

Bu two screen layers, I thought it was on the plenum. Your correct in the two screens, one on the plenum and one half way up. However a problem with that method, is as the gravel dissolves, more is added. Would not the gravel between the screens dissolving, drop the top screen down towards the bottom screen and further from the surface, as new gravel is added.

 

[Maxx]

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?

The idea behind the powerhead was to be able to remove sludge from underneath the plenum.

Is this system intended to function also as a denitrifier? If so then why minimize the anaerobic zone?

yes it is intended to work as a denitrifier in addition to other things. What do you mean by minimizing the anaerobic zone? Is the plenum itself not deep enough?

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.

To be completely honest here, I have no idea if this is the case or not. I don't have access to the microbiology texts that you guys are using. Where did you find this stuff? I would love to do some more research on it myself....Another question: Hows does changing the environment from anaerobic to aerobic cause the bacteria to crenate? We're not talking about osmotic shifts in salinity here, just the addition of O2 to the environment. I'm not asking to be rude...just genuinely curious.

Just thinking aloud. I think I'm going to regret this.

What??? Not at all! We all welcome your input RC...I don't know any more about this than you do, and I suspect you know alot more actually. I know several people (myself included) were less than happy a few months ago and sounded off about it. That was then, this is now. I don't think thats what you're talking about in this case, but if you are...no worries man. I am always glad when people chime in and ask questions or want clarification. If you can't explain something to another person and have them understand it, then you don't have a firm grasp on what you're doing.

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

Doug, how would you deal w/ the detritus build up under the plenum then? Do you feel that any detritus that collects under there is alright or not generally harmful to the system? Just wanting clarification...
Nick

 

[Scooterman]

Cos, good thoughts, I respect that and to some degree I have to agree, this is starting to get way to complicated. In all honesty, I think you either do it properly as Jaubert & keep it simple or move on to another system, like plane ol rubble base, cc or BB or Star board for the matter. If this modified system is to work, it has to be kept simple(which I think it can) but when you start running a plumbing network underneath, your asking for more potential troubles. Now that said, in a larger system umm lets say 500g or more, then yes because your variables have changed drastically but the average reefer in home smaller type, I think if not kept simple then it is asking for trouble.

 

[NaH2O]

Gaaaa, I've lost my train of thought....go figure. A lot of good points made here. Rogue, it's good to see you jump on this thread. I disagree with Scooterman on the point of this being too complicated. I feel that the complication is in determining what will happen when it's drained (will there be another cycle?)...Another point I thought of is on the types of bacteria that will be present. This type of system may have different types of bacteria than a conventional plenum due to the fact that we will be "forcing" the anaerobic bacteria to be "aerobes"...make sense? or am i confusing myself?

 

[Flatlander]

In all honesty, I think you either do it properly as Jaubert & keep it simple or move on to another system, I think if not kept simple then it is asking for trouble. [/B]

Could not agree more. In my experience from reading of failures, most were related to making modifications to the system.

Of course, nothing wrong with trying an idea. Its how we find out things.

Nick,
In all my talks and reading of some experienced plenum people, I have never heard mention of crap under the plenum being a probem. It would be interesting to hear if any with longer term plenums, found anything in theirs, when dismantled. I never had any in my 60g cube, after 2 yrs. There was no detritus to speak of, only partially dissolved gravel.

I,m going to look somemore for info on that.

 

[Scooterman]

Maybe I'm not understanding the entire process, can someone give a summary that is simplified & to the point?

 

[mojoreef]

Rod its great to have your input, the more folks the better. Ok let me see if I can address a few things.

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.

Bro you lost me here. However I do remember the articles you are talking about (Hovonec??). Anyway Nitrosomunous and nitrobacter are both areobic bacteria and thier part is in nitrification, so they always live in an oxygen saturated enviroment. Nitrospira is also an areobic bacteria that reduces nitrite to nitrate. This is still a oxygenated process so I am a little lost on the nitrate and explostion thing???
On the critter population and divercity, The concept is to create an areobic zone that stays oxygenated and does not slowly decline to an ananerobic state. In keeping this area areobic it makes it via for critter that fix oxygen, ie pods, worms, nematodes and thier larve. On finer particles I ma not sure of what other critters will just populate those types of areas, do you have any info on that?? thanks

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

The denitrification occurs in the plenu zone not in the bed, although some may still occur in the bed.

Mike

 

[mojoreef]

Man its hard to keep up, you folks are on the ball today,lol

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.

Possibly, I through the 3 inch depth out thier but we havent really gotten thier yet.

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.

The monaco systems are very large and have a light bioload. I dont think we should have any oxygen getting into the plenum zone, so I am lost again, did I say that??lol. What I was striving for was to keep the particle bed well oxygenated. Cos I wasnt changing the particle size from the Jeaubert plenum, they use particles in the 5mm zone, that is kinda where I thought we were at. As per the ability to go anaerobic I believe they have shown this to be easily accomplished??
On the cleaning of the plenum zone I am up for any scenerios you may have. The concept with Sand bed system is that they only offer the exportaon of nitrogen based products, so i see an ammount of other things entering the bed and not being processed, now couple that with bacterial flock die offs, also unprocessed waste and we should find a way of removing them, if not they will surely build.

Mike

 

[Scooterman]

It is hard to keep up at this place but so Kool that ReefLady took it to the next level!
Oh yea Plenums, got off track again!

 

[mojoreef]

LOL Scoot I here ya bro and I think its going to be a simple system, its just the working out the kinks right now that seems to be a bit complicated, better to work it ut here then to through it in with out understanding it. On the other system I here ya and I would love to do those to.
Doug here is my line of thinking and maybe I am off base. I see the plenum system as set by Jeaubert, it is sucessful but incorporates massive water changes and a low bioload. Both of these we dont usualy have in our home tanks, so the mods were to accomadiate this. For elemental replenishement most of it comes via the water changing but is also buffed a little by dissolution of substraight. So here was what I was thinking. I want to go with basically the same sized particless that they are, I believe these larger particle help maintain the integrity of the areobic zone and that helps with nitrification and accomodaites oxygen breathing critters. I do see an ammount of dentrification occuring in the lower parts of the bed, Also an ammount of isolated areas do it to. Now with a larger bioload and smaller plenum size we are going to have more food hitting the bed and not being processed or just building up. I dont think the bed can keep up with it (same thing with a dsb) So this brought me to two ideas control the ammount going in or clean out the ammount that is in thier. With the flushing of the plenum area you will pull out the dust, bacterial flock and end product detritus that the bed will not process, it will also pull some of the unprocessed food/waster from the lower zone of the sand particles down and out. thus an occasional flushing. Yes it would temporarly slow down the dentirification process, until oxygen was depleted in the plenum zone, but that should not take longer then a day to go anaerobic once again . Population growth of the bacteria will raise quickly as the food source increases, since in flushing we have taken out most of the detritus being processed above it will take a few days for it to once again be positioned in the areobic zone and then a day or so for it to be processed down to nitrate, this should be fine for the repopulation of dentrifing bacteria. Remember we are not starting over in any of the zones, the bacterial base is still thier and in the areobic zone we are really not inpacting it on a bacterial level.

Ok I need to go back to sleep now, lol

talk to me

MIke

 

[mojoreef]

its hard for me to scoot, lol

mike

 

[Scooterman]

I can't agree with that completely!
If your plenum is as big as your bottom, you use a suction vacuum once a month, your removing lots of waste within the larger rocks, I say this from having an UGF with large pebbles, when I sucked it, I removed large portions of unprocessed food & waste. I had a heavy load of FW fish, pooping & feed every day. When I would tear down the UGF, it was nasty but I never killed a fish in doing so, I'd vacuum thoroughly first, then move the rubble all to one side vacuum underneath the grid & then do the same on the other side. Now if this is the case, all you need is a simple drain in the middle bottom with a valve of some sort & maybe a hose to attach for your waste removal but I would do the flush every month after vacuuming the pebbles first & changing water once a month like all other system. SIMPLE! Ok I may be way off base here but this is what I'm thinking, nothing to back me up.

 

[mojoreef]

Yea Scoot we are on the same page, I think. Just in the lower plenum zone I would only clean it maybe twice a year.

Mike

 

[ScottT1980]

If only Jaubert were available, then he could give his opinions...

I found his email address (I think), should I invite him

FWIW: jaubert@unice.fr

How awesome would that be to get his insight into the evolving model that we are proposing.

Take er easy
Scott T.

 

[Scooterman]

If it will survive one flush, it will work on a monthly basis also but probably not necessary.

 

[Flatlander]

For anyone wanting to read an excellent plenum article, I gave the link to Sprungs somehwere here.

Mike,
Jaubert did have the systems you mention, but in Sprungs article he mentions that some of his systems were similar to ours. Closed systems. And FWIW, Julian also mentions that Jaubert later changed his mind on the plenums ability to keep up with calcium demands.

The calcium problem, which was popular in earlier plenum stories, went out of style and it was believed the same additions as needed in a non plenum tank were required, THAT is until Galleon wrote his article. Thats one of the main things I have tried to take him up on, but he is always to busy with his studies.

Ok, I,m gonna take my tank down this time and put a 2in. plenum in, 4in. of crushed coral, and limited rock. :laugh:

 

[RogueCorps]

Originally posted by Maxx
What??? Not at all! We all welcome your input RC...I don't know any more about this than you do, and I suspect you know alot more actually. I know several people (myself included) were less than happy a few months ago and sounded off about it. That was then, this is now. I don't think thats what you're talking about in this case, but if you are...no worries man.

Oh no no... I'm not talking about "that." Actually I can't remember who "that" or what "that" that was. I just meant that I might regret getting into a thread where the complexity might cause a brain crash.

Another question: Hows does changing the environment from anaerobic to aerobic cause the bacteria to crenate? We're not talking about osmotic shifts in salinity here, just the addition of O2 to the environment. I'm not asking to be rude...just genuinely curious.

Oh no, not taken as rude at all. This was what I heard from Toonen (I read a lot of Toonen btw). He was making a point that "sand stirrers" such as gobies, stars, and other large animals aren't necessary and that small amounts of turbation by millions of smaller animals, polychaete, nematode and smaller is sufficient. Larger animal and manual "human" stirring is detrimental because anaerobic bacteria dies quickly when put back into an oxygen rich environment.

Bro you lost me here. However I do remember the articles you are talking about (Hovonec??). Anyway Nitrosomunous and nitrobacter are both areobic bacteria and thier part is in nitrification, so they always live in an oxygen saturated enviroment. Nitrospira is also an areobic bacteria that reduces nitrite to nitrate. This is still a oxygenated process so I am a little lost on the nitrate and explostion thing???

Hmm... ok, I'm out of info on that, but this is another Toonen said thing that a survey of 200 american reef tanks was taken that found that Notrosomonous and Nitrobacter weren't present at all, and that the active bacteria was nitrospira.

So, denitrification occurs in the plenum zone. Is it just done by bacteria in suspension then?

If your plenum is as big as your bottom

HEY!!!

-Rogue

 

[Maxx]

all you need is a simple drain in the middle bottom with a valve of some sort & maybe a hose to attach for your waste removal

Hmmm.....sounds familiar.....

Jaubert later changed his mind on the plenums ability to keep up with calcium demands.

The calcium problem, which was popular in earlier plenum stories, went out of style and it was believed the same additions as needed in a non plenum tank were required

Isnt this what the calcium reactor/ nilsen reactors/ additives were all about? Are we considering this as a substitute for these things and if so why? My understanding of what would be a good system (within the confines of this discussion) would be 2 remote plenums, under shallow, slow water flow, with at least 3-4 inches of substrate, sealed from light. Substrate will be approx. 5 mm in size, sitting on a two screens, one on top of the other. One of these dual remote plenums would be vacuumed out at least every 6 months or so, (alternating) to remove detritus, bacterial flock, uneaten food, crap, etc and allowed to "recover" from the influx of aerobic water into the anerobic zone, (under the plenum). While this "recovery" was going on the other plenum would handle the full responsibilities of the system. The PVC plumbing that is under the plenum or the bulkhead fixed to the bottom of the tank and connected to a length of hose is there soley to drain out detritus that accumulates beneath the plenum and this would be done also at a semi regular interval...say every year, alternating??? Maybe set up a plan to alternate the vacuuming of the substrate and the cleaning/detritus removal from under the plenum? IE...Set up plenum A. 6 months later establish plenum B. At the one year mark for plenum A, vacuum the substrate during a water change. At the one year mark for plenum B vacuum the substrate. At the 18 month mark, drain/clean the detritus from under plenum A. (This is not breaking down and scrubbing the plenum...just using either the PVC and Powerhead idea mike had like in the previous drawing, or using a bulkhead which has been mounted to the bottom of the aquarium strictly to pull the detritus out from under the plenum.) At the 18 month mark for Plenum B, (now 2 year mark for plenum A), we clean/drain the detritus from under the plenum. The whole idea being that we can keep the plenums clean and free of overwhelming detritus which many suspect is the cause of Old Tank Syndrome, and yet always have at least one plenum operating while the other is building back up a anaerobic space. This is not meant as a substitute for a reactor, or using Kalk or additives. This isnt designed to do anything but remove nitrates while preventing phosphate loading/ sinking.
Was everyone able to follow that? Does this seem like a viable solution? Have I left anything out, (outside of the PITA factor) ?
Nick

 

[mojoreef]

LOL DOug hurry up,lol. I agree with you on the replenishment, I believe Toonan just did some comparison tests and found a small amount, I dont think it would be anything that we could rely on what so ever.
Chris did do a good write up, but I would say one with out experence on the product itself.
The reason for going down this plenum path was to see if this system could provide what most folks want to get from a sedimant system, Ie: bugs, dentrification. And be able to do it with in a system that would not have some of the inherent problems the other systems have. Thus the modifications. I was also looking at it as an addition to a setup tank, just as someone would setup a reactor or a refugium in order to draw some of the things they liked about what that system offers. Is it going to be a better dentrifier then a DSB?..no will it supply enough cal for our tanks on its own?...no. Will it have all the life that a DSB is said to have?... no, But I think it would supply an ammount of all of those things without the drawbacks involve in those systems (with the exception of the reactor) so anyways that was my approch to this.

RC I have read several papers on that subject to, I believe it had to do with both FW and Marine. In the wild you have the Nitrosomunous and nitrobacter and most folks assumed it was the same in our closed systems, but it was proved that nitrospira was actually the bacteria present (must have had something to do with something in a closed systems) regardless all 3 of these bacteria are nitrite oxidizers and dont pertain to the anaerobic zone.
On the dentrification it does occur in the plenum zone, in the solution and on all the surfaces present, for sand to dust to organics and so on.

MIke

 

[Cosmic]

Ok,
Know I know you explained your reasoning behind why siphoning that plenum space out isn't going to hurt anything, but it still goes against everything that has been born, bred, and beaten into me

I think that the only way you are going to be succesful is to try to manipulate that drainage system on a closed, anaerobic loop of sorts. Anything less and the system is going to undergo a "hiccup" which could be detrimental to the health of it's occupants. Any time you go about disturbing a bacterial population, you are going to hinder the tank's ability to maintain itself. Shut things down for a few days and go home is yet another way to put it.

I think if you can find a way to replace the plenum water with "clean" plenum water, that you might be onto something here. The easiest way I know of doing this is to draw that water out, run through a sediment/particulate filter, and pump it back in.
Then you can remove the sediment filter for cleaning until the next time.

Again, something like a magnum 350 would be a cheap route, although for a high-end system you would probably want to consider an external pump and a closed loop canister solution from aquatic ecosystems or maybe Rainbow Lifeguard. Install a few ball valves to allow for removal of water, and to insure the filter can become anaerobic again before using it.

This method, IMO, would not inhibit the tank too much because your are simply straining the water of debris instead of drawing fresh aerobic/oxygenated water through the substrate.

One downfall of this method is that you are not "rinsing" the bed so to speak. However, with good top-bed management, along with the large grain size (5mm) and ease of debris removal from the plenum, there's no reason it should be an issue for a LONG time to come.

I know normally that a pump being turned on after having sat without power for awhile can be harmful to the tank, BUT, that's because the water is anaerobic and a much lower pH. A perfect match for the conditions we are trying to accomplish under the plenum.