Jaubert Plenum

[mojoreef]

YES!.........Clean sand won't clump right?

yep it can scoot, it can melt and then fuse. This is another reason for good critter stirring, with that you can avoid it.

YES~~~~~Will waste clump anyway, maybe just smaller more managable clumps?

What happens in sediment beds is that the waste/food/dtritus/enzynes/microbes and so on form a type of bile, or reef snot as we used to call it, lol Examples are, when a worm swallows the sand, then poops it back out, a bunch of other stuff comes out with it (slime from the digestive tract of the worm) also when bacteria reduce things they just dont go up to it and chomp they use enzynes and acids to melt it first then they suck it in. On a side not I believe more elemental replenishment comes from that then lower ph. So you got a stew in their no matter what. Now bacteria live in this world and no how to get things done in that enviroment, but they can also get overwhelmed, this is where build up and clogs occur (example: big clump of food gets stuck in a corner under a rock, well you can kiss the filtration efforts in that zone goodbye for awhile. The enviroment has just changed in that area, now thier is an anaerobic zone right on top under that chunk, with the areobic zone surrounded the tops and exposed) thier is nothing static about a sand substraight.

Coug about time, lol great to have you in here, and your questions are dead on.

As I understand things, there is a problem with aragonite based substrates binding phosphates (along with other undesirable things). In a plenum, there is an acidic layer that will slowly dissolves the substrate helping maintain the calcium levels in the tank. Would this not release the phosphates back into the water to do more damage?

Excellent question and yes that is the main problem, but what we are trying to do is to solve that problem. What happens is that the ph decreases the further down in the bed you go, the lower ph melts the sand and thus releases the what ever is bound in it. So in 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, tough to explain, tell me if I didnt.
In regard to the balance coug we are looking at a remote system, with no rocks on top, we kind eleminated that intank concept earlier.

Mike

[Maxx]

Nick the concept regardless if just draining or using a PH, is that Oxygenated water will take over position in the plenum zone (not air). This oxygenated water will stop the bacteria from fixing oxygen until they use up the oxygen in that zone, then once again they will fix nitrate. When doing this flushing no air can ever be aloud to get in thier, Which is easy to accomplish.

Mike, I understood what you meant, I was just clarifying for Scooter.

As for adding a drain system to the bottom layer of the plenum, how effective would that really be? Wouldn’t you need a strong current to ensure that the debris gets pulled into the drain? My concern is that the debris has had time to settle on the bottom of the tank and wont want to move very easily.

Michelle, for purposes of this discussion, assume that the plenum drain is at least 1- 1 1/2 inches in diameter. This should suck out whatever is in there. If its done on at least a 6 month interval. If your not gonna get it out w/ a gravity drain that size, I doubt that a power head attached to PVC plumbing will work either. Just my line of thinking, could be wrong....

Nikki I love it This is the way good things happen, no more here has monitary motives (no books to write or speaking engagements) this keeps the conversation pure, we have folks from many different schools of thought all putting in thier knowledge, it dont get better then this.

Mike I agree, no worries about the financial mind influencing the discussion.
Nick

[Scooterman]

Yea, I can't Afford to have financial influences!

[Curtswearing]

Originally posted by mojoreef
yep it can scoot, it can melt and then fuse. This is another reason for good critter stirring, with that you can avoid it.

I saw a picture on another web site where they didn't have sand stirrers and used too small of sand particles and the whole sandbed turned into a huge brick.

[Scooterman]

Humm, things you never even think about, I say!
I'm interested to see what is derived from all this.

[NaH2O]

Alright....who's going to try it out?

[Curtswearing]

Not me.....at least not yet. I'm doing too much reading and I don't think we have solved all of the issues yet.

One of the differences with a plenum is the 2 way migration and that's a good thing in my book. It's one of the reasons I was going to put my DSB in my fuge----so I could take it offline and maintain it easier with less risks. DSB's are strictly a 1-way endevour. The ideas in this thread might make the maintenance easier but I'm still trying to work some things through in my head. I'm trying to think of O'Malleys law which in a nutshell is ignore Murphy----he's too much of an optimist.

[Cougra]

In regard to the balance coug we are looking at a remote system, with no rocks on top, we kind eleminated that intank concept earlier

Missed that part somewhere along the lines! At least now a lot more of this discussion makes sence!

I understand what you are saying about the Phosphates desolving and being bonded again very quickly but it still doesn't solve the overall problem of it eventually saturating the system and leaching back into the water.

Seems to me we are going around in circles if we are going to souly rely on the plenum to do everything for us. Removing sections of the substrate regularily would revitalise things and be an export for the phosphates. Unfortunately this can become a costly endever with larger plenums.


PS Why do I feel I'm going to get a big headache stepping into this conversation?

[Maxx]

The new issue of FAMA Dec 03, has an article in the Reef Science column by Charles Matthews titled "Fun with Plenums".
I havent had a chance to read it yet, but in skimming through it I noticed that the author admits to being a Miracle Mud fan, and that Plenums have kinks/issues that need to be dealt with. Towards the end of the article he makes a couple of reccommendations....which I havent really read yet. To be honest w/ you, this article is the whole reason I purchased the magazine. I find that this magazine and TFH tend to be geared towards the rank beginner, and as such doesnt have alot to offer me. I'm not trying to be ostentatious or arrogant, just honest. So I'm not really expecting a whole lot of mind blowing stuff out of this particular article, but I am hopeful. I will give you all a heads up tomorrow....assumiong you havent rushed right out and bought your very own copy by then.
Nick

[Maxx]

I understand what you are saying about the Phosphates desolving and being bonded again very quickly but it still doesn't solve the overall problem of it eventually saturating the system and leaching back into the water.

Michelle,
I agree w/ you that this is something to be aware of, but the beauty of having it remote is so that when it starts to hit saturation point, you can take it offline, break it completely down, (if really needed, removing portions of the substrate on a regular schedule, say every 6 months, should alleviate this problem), w/o any real ill effects on the main tank. If you wanted to go crazy w/ this idea you could set up the a remote plenum, after a year start a second remote plenum. At the 6 month mark the first plenum will have been in operation for 18 months,and can be completely broken down, scrubbed out etc, and then set back up. This would allow the system to run as normal since it still has a plenum system in operation. Does this make sense or just cause headaches?
Nick

[NaH2O]

Originally posted by Maxx
If you wanted to go crazy w/ this idea you could set up the a remote plenum, after a year start a second remote plenum. At the 6 month mark the first plenum will have been in operation for 18 months,and can be completely broken down, scrubbed out etc, and then set back up. This would allow the system to run as normal since it still has a plenum system in operation. Does this make sense or just cause headaches?
Nick

Makes sense to me, but it also may cause headaches if you don't have a separate room for the equipment....

[Flatlander]

[i This is the way good things happen, no more here has monitary motives (no books to write or speaking engagements) this keeps the conversation pure, we have folks from many different schools of thought all putting in thier knowledge, it dont get better then this.
I think Doug will agree this reminds me alot of the old days.
Mike [/b]

For me, the old days computer wise, was the late 90,s.
Before that is was magazines or books. You,re correct, in that these threads have excellent info and ideas for us.

Nick, thanks on the tank. I took it down and sold it, when I purchased my 225. In later though, perhaps the dumbest thing I did. It was a beautiful size tank and could be lit with a single 400, with a bit of help. After owning a 6ft. 30in. deep tank, I would go back to the cube style anyday.

Michelle,
The idea with the rock rack is ideal for a plenum tank. If a plenum is done in the show tank, then the rock should be limited or kept off the bottom. This provides for a better diffusion through the gravel and allows for easy cleaning of the bed itself. Sprung likes the idea of limiting the rock, because of its coralline encrusting. That, of course, consumes vast amounts of calcium. My large reactor barely keeps up to it in my tank.

Back to the cleaning topic. Mike, if you remember in talks with Sprung and other threads, there seems to be not much sign of a detritus build up, in a correctly functioning system. Esp. if siphon cleaning of the surface is done regular. Also we wondered about the dissolving gravel, near the bottom screen, from the lower ph. Remember we wondered about it plugging up the screen, but it seems it just keeps dissolving, perhaps falling through and then dissolving completely.

[mojoreef]

Coug the brand new sand and or gravel you put in your tank is already at saturation level before it ever makes it into your tank. What happens in our tanks happens in the wild the same way, just look at the florida bay problem.
Anyway the key is to not allow it to come out of solution. The way it comes out of solution is by a reduction in PH in the lower end of the bed. In using larger particles and good water flow and in keeping the bed areobic we are not allowing the ph to drop in this upper zone. What this gives us is a well areobic bed (with all the critters everyone want) and with the ability for nitrification and for denitrification lower down and in the plenum zone. The main source of Phosphate problems are not really associated with the disabsorbtion of the sand particles but in reality is with the organic forms that are assocaited with detritus/bacteria and vegitation. This is where we really need to go after controling it. So far we have come up with a few good plans. With the use of larger particles we are going to eliminate alot of the clogs that occur in finer substraights, it is also going to allow for a much larger and deeper areobic zone for areobic nitrification. the flow coupled with size of particle is going to allow for easier migration of food sources to the anaerobic zone denitrification. Now were are going to have phosphate build up still in the bed, but nowhere close to a finer substraight bed. This cycle as it is with any substraight is basically phosphate to algae then to animal(bacteria) then then back to algae again. In order to control it we must break it, export it and control its input. So input is by watching what we add (ro/di, perservatives in foods, over feeding and so on). In controling it we have the above larger particle , keeping the bed areobic, sucking out the excess and end product detritus through a plumbed system in the plenum zone. In breaking the cycle, we again have the keeping the bed zone areobic, stirring the bed occasionaly to remove excess, 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).
Anyway that where I see us so far???? whatcha think.

Doug

Back to the cleaning topic. Mike, if you remember in talks with Sprung and other threads, there seems to be not much sign of a detritious build up, in a correctly functioning system. Esp. if siphon cleaning of the surface is done regular. Also we wondered about the dissolving gravel, near the bottom screen, from the lower ph. Remember we wondered about it plugging up the screen, but it seems it just keeps dissolving, perhaps falling through and then dissolving completely

You bet Doug. With the larger particles and good water flow I dont even think stirring would be need. On the dissolving, thats the way I always saw it, and again I think the occasional sucking from with i the plenum should pull down the finer stuff, suck out the excess detritus and export the end product that would be building in the plenum zone. The down point of this suction is temporary loss of the anaerobic zone, but that should come back quick, man you could even reverse the pump and inject you reactor effluent.

MIke

[Maxx]

Whats the feasibility of setting up 2 remote plenums, (1 year seperation between start up), and when taking one offline for cleaning, gravel washing the snot out of it. I know that in gravel washing we basically "kill" a plenum, but wouldnt the 2nd one (if appropriately sized) be able to handle the bio load while the "washed" one came back online and begain to function properly, like in say a month? The benefits to this would be almost complete removal of detritus from the gravel bed above the plenum, and we could also simultaneously flush/drain out under the plenum to get that cleaned out as well. That should be able to restore the plenum to 100% in short order shouldnt it?
Nick

[Curtswearing]

I think a lot of the above is very interesting. I still see the need for a light bioload or a very large plenum. Even using larger particles, I still see the possibility of fusing unless a balance of calcium/alkalinity is maintained via a calcium reactor. In theory, with a consistent melting of CaCo3 this should never happen but in practice a lot of things can happen.

What if ph was accidentally allowed to drop? I still see the possibility of too much phosphate being allowed to unbind possibly overwhelming the ability of the CaCo3 above it to "re-bind" it. I can see something like this happening. I.e. The main pump siezes up. The lack of circulation causes the D.O. to drop and the CO2 to increase. Then the pH will drop. If this happens, how big do the the sand particles need to be to not fuse?

I'm not trying to be a pain....just trying to get a handle on the situation.