Jaubert Plenum

[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*

>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

[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]

[i] 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.