trickle tower/external filtration-why do they give MORE nitrate?

[HighlandReefer]

I am enjoying this thread. A lot of good info. coming out in each of your posts. You two are working hard for your money.

That said, I use a deep sand bed myself and find through trial and error, since it is a remote sand bed in a 55 gallon plastic drum with about 6" of sand on the bottom, that it does remove the nitrate in my system. IMHO, the deep sand bed has to be fairly large to offer any benefit. I have read many threads where hobbyists have tried 5 gallon containers where they fill there was success. I would recommend a larger deep sand bed than a 5 gallon container for most larger systems, to provide enough benefit.

 

[tmz]

Registered Member





Still twisting and turning I see. blah blah blah....lol

There you go again making it personal.Again as a matter of record don't resort to harassing private messages again either .

It should be obvious to most that you have a problem with debate and disagreement that is quite detrimental to learning and are clearly without any intellectual integrity if a particular point of view doesn't suit your original statements.

Your last post is false in terms of your wild intrpretation rewrite of my posts and absolute nonsense.

Suffice to say you haven't read my post or even the research you introdcued ; just can't understand it; or choose to deliberately misrepresent it for some narcissistic motive.

Fortunately it and my other posts are in this thread as are yours . Folks can read them with or without your editorial sewage and sort out the facts for themselves.

Obviously your compulsiveness will require that you have the last word and I'm really bored with your nonsense and don't care what you think or feel or confuse . So I will make it easy for you by not responding further to you in this thread.

Finally,once again and for the fif th time stop the personal attacks . They have no place in this discussion and violate the RC process.

 

[therealfatman]

.

 

[therealfatman]

I typically run two RDSB on a 120 tank with 40 gallon sump holding approx 25 gallons of water. The tanks do not contain fish. I have found a 5 gallon RDSB for each 70 gallons adequate for coral only tanks with no fish or low fish populations. I have found in my SPS tanks that 2 RDSB perform as well or better than a 4.5" to 6" deep in tank deep sand bed, with fewer problems and a grate increase in usable tank volume.

There is always reserachand being done of biological waste processing systems.

I would love to see a study of a remote deep sand bed with specific bacteria innoculations of bacteria that do not require the organic carbons to form N2. There have already been patents issued for systems for aquatic farming filtration systems. Time will tell.

 

[wayne in norway]

Like I have said from the beginning RDSB's work and advection assistance isn't needed to accomplish that ability to perform. The advection at most merely returns what you have removed in the way of performance by covering most of your sand bed in an in tank deep sand bed live rock system. The touted research you have provided likely just shows that strong circulation caused advection can make up for the decrease in bed surface area brought about by the coverage by live rock.

You believe that diffusion is providing an adequate flow of oxygen , nutrients into the depths of the sand bed? I find that very hard to credit, but in a very low flow situation it would likely backup up a depth > 2.5 cms not making a difference. Personally I like to run a very high flow rate and make use of a far larger sand volume.

 

[tmz]

Clifff,fyi, fwiw,

I use a 30 gallon bin with swift flow over 7 inches of sand. I have placed 4 inch high live rocks on top of a bout 50% of the approximately 4.5 sq ft sand area.

I also use a deep sand bed(4inches) n a 90 gallon tank with 6 sq ft area(this is my oldest tank 7yrs) .

A 30g breeder tank(4.5 sq ft) used for frags compliments with a 2 inch bed.

Two other display tanks on the system( a 120 ga nd 89g) have shallow sand 1 to 2 inches.

All of this is integrated at the sump with a couple of chaeto refugia and a cryptic bin with live rock for the 550g system.

 

[tmz]

Hi Wayne,

Sounds like we see diffusion the same way.

I think the addition of live rock as structurte over a portion of the bed does more than just replace the sand area it covers though. In the cited model(Sprung and Delbeek) which is based on a mini reef structure ,the water is pushed/ pulled into the sand by advective flow to a depth equal to the hieght of the rock into the area directly under the rock and then rises up under and into the rock. So if the rock is 10 cm high for example all 10cm of sand under it would receive the flow not just the typlical 2.5 at the surface. I also think this type of movement would ripple out beyond the rock's actual footprint at least a little.

 

[therealfatman]

Advective flow: First lets consider a fair sized Acropora gemmifera_ (?) 8 inches in diameter, saturation was reached at approximately 0.8 feet per second. (roughly 20 cm per sec). Saturation here being the water velocity needed to remove all detritus from all areas of the coral head. It is certain that different shaped and sized coral heads will require different flows. Placed too close, living tissue can be ripped away from the skeleton; too far away, the animal will suffer when detritus collects between the branches. Riddle, D.

This research you address is pretty ludicrous in expecting a test reef to a typical aquarium owner by expecting a flow velocity along the surface of the substrate flowing under the rock at a velocity of 10 cm per sec. At best this my happen a few places around the perimeter of the live rock pile. Especially now when the fad is propellor pumps (placed mid level) which produce large flow volumes and small velocities. I do not read much of those pumps being placed at the bottom of the tanks. The typical tank has the lowest flow velocity along the sand substarte. I doubt that 10 cm per second condition would be plausible even with intent for those using aragonite sugar sand (the sanded touted as best for deep sand beds) as sand clouds are not usually considered beneficial in a reef aqaurium. I am sure if you have ever walked in the ocean you have experienced the feel of sand washing from around and then under your feet. Sure that is not really the same but the results would likely be the same. While that would not prevent its theoretical application for larger particle size substrate I have not heard of aquarists needing additional flow with larger particle sized substrate.

The theory does I think have a capability of increasing flow into the deeper depths of a RDSB by simply using a large salad bowl attached to the lid of the bucket that extend down to the substrate surface. A layer of larger substrate at the top of the bucket would prevent a sand storm effect causing release of sand out of the bucket. The brisk flow would prevent a lot of detritus from lodging in the larger substrate.

With some effort a flow of water with a velocity at 10 cm per second is likely possible in a method that will not cause a snow storm bot it would likely have to be done with a large diamter manifold behind or under the rock moving a large volume spread by fan tip exhausts. It would be close to if not impossible to supply the flow at that velocity with power heads as they have laminar flow so distancing of a foot or more from the rock would likely be needed. Maybe propeller type power heads might work but I do not know what they actually supply for velocities only that the are less than the old style power heads.

Cost wise for implementation and ease of operation and maintenace considered I still believe the RDSB would be a viable aqaurist tool for nitrate control, and yes incorporation of advevtion witha bowl or some such thing could help. One must consider though that aq single or a few buckets will not handle denitrification for a multi hundred gallon system with a large bioload. However large RDS beds can handle the loads as is proven by the hundreds being used by public aquariums.

 

[tmz]

For the sake of clarity.

In the model cited the flow rate colliding with the rock is 10cm per second.
As current hits the rock the water pressure changes. The change in water pressure causes the upwelling under the rock..
The speed of the upwelling water(endo upwelling) in the model is 1 cm per hour when the flow rate of the current is 10cm per sec. Didn't go into all this detail earlier but it seems necessary now to keep things straight.. Advection makes the water flow down and back up under the footprint of the obstacle. This is how natural reefs work in terms of the provision of nutrients throughout their structure.
While any obstruction will block the water ,the depth and area of advective flow into the sand is related to the height and footprint of the obstruction. The advective flow mirrors it in the substratum. Don't know if the obstruction needs to be permeable like live rock is for advection to work.

I opted for live rock in the remote sand bed because the rock has a degree of permeability which allows the water to move upward through it further enhancing the denitrification processs in anoxic areas of the rock. Not sure if the endo upwelling flow rate would be the same if and an obstruction with a non permeable bottom were used.

Since I consider research and advice from Sprung and Delbeek to be of high caliber and certainly not ludicrous I followed the model and used rock.

Sprung and Delbeek also note : "The flow of water into the substratum by advection also results in the transport of particles and disolved substances from the water column into the substratum."

 

[therealfatman]

" Details are very important."
I under stand what your talking about and very likely a great deal more than you, Sprung or Delbeck understand it. Your talking about nothing more than any civil engineering undergraduate student covers in their engineering studies of fluid dynamics and water resources engineering. I can only assume there knowledge is minimal as it is outside their fields of study. I do not believe they have studied, much less obtained degrees in civil engineering or further that they obtained upper level degrees in hydrology or even took upper level (graduate) courses in Hydrology.

Advection commonly is the term one uses when one is concerned with the transport of sediments. Typically this means designing a system that has a particle size that will stay in place based upon the maximum expected velocity of the water flowing over those particles. Some would just say siltation control in rivers, stream beds, along shorelines etc. Why they would use that terminology in dealing with increased verticle penetration due to horizontal flow interruption caused by an overlying object is something for them to answer as typically one is dealing with undercutting under the conditions they suggest. Then they are dealing with sediment transport and herefore advection. Perhaps they were just grasping at threads for terminology to fit a circumstance they could not adequately explain due to it being outside their fields of study, at least I have not heard of them having degrees or even any study at all in the fields of hydrology. If you wish I can PM you a list of the courses I have completed in the fields of Hydrologic Analysis and Design, Water Resources Engineering, Hydraulic Engineering, Fluid Mechanics or Computer Applications of Hydraulic Engineering etc..

If you drop a solid object (large concrete block) on a river bottom such as a pad to place a temporary work pier on top of, you must deal with advection. That advection is the study of sediment or silt transport horizontally. Yes that advection is increased and possibly even caused by the block of concrete and possibly the water velociyy would have been inadequate to raise and move the particles now being carrried by the water prior to that concrete pad have being dropped.

The very sentenced you posted shows they have limited understanding of the processes or the associated terminology or that you are wrongly using their sentences out of context.

“The flow of water into the substratum by advection also results in the transport of particles and disolved substances from the water column into the substratum.”

Particles move in a waters flow above the substrate surface due to the process of advection. Advection is caused by flow of water under individual particles and by the flows velocity carrying that sediment load. Advection is not a term that describes the process they are trying to describe or probably theorize as I very n much doubt that they set up piezometers to test their hypothesis they are calling advection.

I more than adequately described what the normal person experiences in regard to advection when I wrote of the sand moving under your feet while walking in the ocean along a shore.

I will go so far as to say in extreme high velocity cases an engineer would possibly determination how deep an influence a particular advection situation might experience but that is more of a secondary discovery to determining particle sizes that can be expected to be moved.

The only other explanation of their use of advection is to use it wrongly to express the horizontal displacement of particles under the substrate surface as advection. Advection is a surface condition of sediment transport not a subsurface condition.

Basically I understand what you and they are trying to express but advection is not the proper term for the situation they now hypothesis about and you are repeatedly using the term advection improperly and out of context. If there is no sediment being moved there is no advection. Your improperly using the movement of water around an under an inmovable object to describe advection. One could extend advection to describe the movement of water under and around a movable object if that object is moved, but not an inmovable object unless they are describing the movement of the sediment around that inmoveable object taht is moving. A condition that may cause advection is not advection. Example: Sex does not necessarily mean pregnancy. A possible cause may not produce a possible outcome. Advection is an outcome and you and your experts are using the term that expresses that outcome to describe some other possible side effect of the conditions that may cause advection but at the same time ignoring that advection is the carrying of sediment in the waters flow. Ie., the term advection is being used improperly by you and your experts.

Previously I used the term adjection, which means in addition to. or adding. What they are describing is an adjection that is not advection.

 

[therealfatman]

<a href=showthread.php?s=&postid=15008547#post15008547 target=_blank>Originally posted</a> by wayne in norway

You believe that diffusion is providing an adequate flow of oxygen , nutrients into the depths of the sand bed? I find that very hard to credit, but in a very low flow situation it would likely backup up a depth > 2.5 cms not making a difference. Personally I like to run a very high flow rate and make use of a far larger sand volume. [/B]

I do not believe diffusion is the only method for nutrients to reach the sands lower depths. I run very high flow rates already. Plenty of nutrients are reaching the lower depths as the flow is adequate and very likely more than adquate. I believe that oxygen is not needed deep within the sand bed because my reason for using RDSB's is denitrification not nitrification. If the nitrification has already taken place in the tank the only additional nitrification needed is to strip the water entering the sand bed of oxygen before it reaches the deeper parts of the sand bed.

Please do not consider the following as an accusation or personal assault as I agree with what you have said and I have no idea what type of tanks you keep or how heavily you load them.

I do not run tanks with massive bioloads so I need merely a well performing system not a system operating as if on methamphetamine because it must remove huge sums of nitrates. If the system has such high nitrates the problem should be prevented not held in check with massive efforts through the use of a skimmer, live rock and the use of remote sand beds, plus GFO, massive amounts of continously used crabon, refugiums, macro algae, vodka dosing etc. It is one thing for a waste water treament plant to have a need to feed its denitrifiers with alcohol etc., but for a tank to have such high demands to place on a deep sand bed denitrifier is not a cause to think a sand bed is working inadequately but instead to consider that the bioloads are excessive.

A RDSB might be small and therefore consider merely like a small caliper weapon, but I am not out trying to take down an Elephant with a RSDB but simply a rabbit/bird.

When the day comes I find I must over stock and over feed a tank so much as to need a handful of extreme measures to maintain nitrates below 2 to 5 ppm I will quit keeping reef tanks.

 

[tmz]

The aesthetics of an aquarium are up to the individual aquarist.

Some prefer just sps tanks with no fish can be quite nice and do not demand much nutrient export relatively speaking unless one is attempting the ultra low nutrient systems. For me many of them but not all are a bit boring. Some are stunning. Some are frag racks but that's really a matter of taste and purpose. .

Other aquarists prefer to keep fish and other marine animals that do carry a higher bioload in mixed reef tanks that include sps .
If the techniques(none of which are generally considered extreme) that are available today for nutrient control are efficiently applied ,it's possible if a bit more complex to have a broader range of choices in creating a mini reef that is diverse and aesthetically pleasing to the individual aquarist according to his or her tastes and artistic sense.

One type of reef is not necessarily better than another nor more appealing to everyone.Less is not more for some and for others more is less. Although I personaly believe diversity of organisms including microbial organisms and food webs play an important role.

Obviously nutrient control is more critical as more nutrients are introduced in a well but not excessively fed system hosting a variety of marine life including fish ,sps , lps and perhaps even some non photosynthetic corals and a gorgonian or two . In this type of system nutrient management must be carefully considered. Knowlege about and hands on experience with remote deep sand beds, carbon dosing, denitrifiers, gfo, graulated activated carbon , ,etc , just put more tools in the creative box. There is nothing wrong with using them.

Of course there are limits to the number and type of specimens you can keep in a reef tank or system of several integrated tanks for that matter but there's still plenty of room for creativity and a pleasing amount of livestock with efficient nutrient management. There is no need to think you have to reduce what's in your tank just because you get a bit of phosphate or nitrate if you are confident your stock level it's reasonable. Just because you take steps to manage nutrients does not mean you have an overstocked tank or too much bioload.It may be the case in some situatiuons but wouldn't be my first guess particularly if I had no idea what was being kept.
Nutrients can be controlled. Finding the most efficient ways to do so is a large part of the hobby. For all of the reasons stated earlier, I do not believe remote sand buckets 9 inches deep or more with rapid flow across the surface do very much and several more efficient approaches exist.

 

[therealfatman]

A salt bucket is basically a free item so the cost to set up a RDSB is minimal. The cost of setting up a 30 gallon tank definitely exceeds the cost to set up a RDSB. A RDSB made from an IO salt bucket has a foot print of 0.54 sq ft. The foot print of the 30 gallon DSB is 3.0 sq ft. I am quite sure that the RDSB will provide at lesat 1/6 th the denitrification of the 30 gallon tank DSB and at a much lesser charge and requiring less space. I have a small need for denitrification and many others have small needs for denitrification. Many aquarists with mixed reef tanks would be estatic with my maximum nitrates levels experience without RDSB and would not take any steps to reduce the nitrates. For my tanks 5 ppm is extreme.

As for efficiency in removing large amounts of nitrates that is your issue not mine. If I want more denitrification because i happen in some individual tank to actually register some nitrate I can jus\t add another RDSB. I am still only needing to remove small amounts so two RDSB is still cost and space ahead of the 30 gallon tank. Actually I could install at least five RDSB and still cover a smaller footprint, spend less and utilize the fact that buckets stack quite well.

 

[tmz]

No doubt ,salt buckets have a myriad of uses and can be very convenient and inexpensive . They rank up there with some of the most useful equipment. No reason they won't nitrify and denitrify with some sand in them. I just don't think you get much more if anything out of the extra depth via diffusion but it probably doesn't hurt anything.

I use a rubber maid bin($10) not a 30 gallon tank for the remote deep sand bed; it is 30 inches by 24 inches ,so it's footprint is actually 5 sq ft, just checked the measurements. The 30 gallon breeder I use as a combination frag tank and sand bed is 3ft by 18 inches for a footprint of 4.5 sq ft.

BTW nutrients have not been an issue for me in quite a while.

 

[therealfatman]

About time!

 

[tmz]

<a href=showthread.php?s=&postid=15023349#post15023349 target=_blank>Originally posted</a> by therealfatman
About time!

:lol: :lol: There you go again.

Attacking someone's tank or husbandry when you have not seen it or know nothing about it is temerarious.

I don't care how many courses you say you took, they were obviously irrelevant to this topic or you didn't learn much if anything you can effectively relate to the hobby.If you did you wouldn't have to make up so much. In any case you're no match for Sprung and Delbeek when it comes to Reef Aquariums in general and specifically on the topic of advection( I repeat not adjection) You have no reason for being so distasteful,offensive and disrespectful to others. Referring to their work as ludicrous is well .. ....

Just because someone disagrees with you and you dig yourself a hole with poor information, misrepresenting others statements,obsfuscation and citing references and terms that are off topic or just don't support your position does not give you a legitimate reason to attack others or the approaches they use particularly as you did me with harassing personal attacks in private messages after you were told to stop.

Since you claim superior knowlege to two of the very well respected names in this hobby and probably most everyone else and suggest they were"grasping at straws" with the advection model previously discussed, it's necessary to provide a little more information for others who may be thrown off by your obfuscating rambling. So here is the source research from the Max Plack Institute for Marine Microbiology,Bremen Germany for the noted advection model:

http://aslo.org/lo/toc/vol_48/issue_4/1674.pdf

and this from it:

"Our tracer experiments indicated that shallow water waves can increase fluid exchange between sandy sediments and overlying water 50 fold relative to the exchange by molecular diffusion....boundary layer flow reacting with the sea bed topography induces pressure differences at the sand water interface that lead to pore-water motion in permeable sediments. The ensuing advective transport can exceed transport by molecular diffusion by several orders of magnitude".

Who's grasping at straws"?

 

[therealfatman]

Must you think every thing is about you or an insult against you. I have not attacked yout tank or husbandry, I just do not agree with your methodology or your misuse of terminolgy. I do not recommend or keep mixed reef tanks and have lawys made that clear on this forum. I alos do not recommend that the home Reef Tank Hobbyist keep any organism that is not: tank bred and raised, or tank grown, prp opagated etc. I do not recommend the Home Reef t Keeping Hobbyist keep anemones or fish caught in the wild that can be or cannot ber bred in captivity. It is widely known on this forum I only use carbon occasionally for water clarity, and I have not used GFO but once in the last year between over 40 tanks. I do not use alcohol or vinegar, sulfur reactors, ozone, UV lights, I have one refugium and it is for viewing pleasure not because it is needed. I use a skimmer, rdsb's, kalkwasser, IO salt, an ATO, daily water changes, and I add calcium and magnesium to my water changes. I add alkalinity by auto supplementation. I feed only live cultured foods, that I gut feed Super Selco as is appropriate.

I flatly keep nothing but ultra low nutrient tanks. I have made that continously well known. If others so choose to deal with high bioloads and all the "stuff" required to control high nutrients that is up to them. I try to offer advice and rebcommendations and share my experiences and knowledge with them even though I only keep ultra low nutrient tanks. bI have kept tanks of all sorts in the past including mixed reefr tanks containing predators so I kno whow to handle huge bioloads and still maintain low nutrients. However, I do not do it anymore and do not sugest bothers do so.

I was saying in my last reply that it is "about time" this thread was closed. No more than that. If one isso vane as to think everything is about them that is on them not me.

I have not provided poor information. My arguments are sound. I repeat adjection is a good not improper term for any increased flow of water such as you previously described as advection. Remember you described advection as incraesedwater flow ot increased diffusion. Now you are back to diffusion and stating diffusion is increased and now post a Url that mainly studies and deals with diffussion and that article advection is said to increase discussion. DUH! I have never said that was difussion was not increased by advection horizontally and that is laall this study assigns to the effect of advection. The argument has always been that what you describe as advection is not advection and that is still a fact. You have always claimed advection is causing increased vertical water flow, and in that you are wrong. PERIOD.
Even the quote you just posted does not support your argun ment. Unless you are changing your argument, which it bseems you are now attempting to do.

The argument is not about diffusion. It is about flow and the only flow advection deals with is horizontal, not vertical.

As far as PM's you wrote I wrote three to you and you wrote three to me. If you do not want a PM back from me do not write to me. The software allows you to block PMs from me if you wish to write me and not have me reply to your remarks just block my PM's. Making comments about it after already having contacted a moderator is not much of a show of maturity. I quit responding to your PMs you sent to me it would seem that was sufficient. However, I am not a past administrative assistant so I do not have a vocabularly of off the wall insults to throw at you as you seem to do towards me in your last reply.

I do not claim superior knowledge to your touted experts I merely claim they are using the field of hydrologies field dealing with advection improperly. Advection is not unidirectional it is only horizontal. Like I suggest later they need to develop an approproiate language and approach to their science to deal with ocean hydrology that advection does not address. At least The German scientists admit that advection does inadequately address their research/studies. Sprung and Delbeek just try to use it even though it is inappropriate. DUH.


TMZ I am tired of your grasping at straw mannerisms. I have read your URL and it does not differ in that advection is as I a tr erm describing and dealing with sediment transport horizontal sediment transport. Even the diagrams and state the boundary flow-ripple interaction causes advection filtering that exchanges pore water of the upper sediment layer.

This in itself explains that advection is indeed the sediment transport in the horizontal direction as the sorting shows.

You trying to a use advective in ways that are not appropriate. Your microbiologists are boredering on doing the same thing and occasionally are crosing the line. Just like the other biologista they are inappropriately using the term advection. Hydrologists own that term as a part of their science and field of study and have no provisions for using that science in the manner in which the biologists are using it. The part of the artiv cle you seem to be using to argue furtheris a study using a die to show plume transport to hopefully compare it to dissolution. In that bstudy they show horizontal transport horizontally due to advection. Yes that is true advection is the sediment transport due to horizontal water flow. Sediment in transport is sediment that is suspended in the water and yes that suspension means increased diffusion and eveen incraesed water exchange in the pore spaces.
The fact that the researchers are trying to find inventive ways to braoaden the use of a horizontal advection by using advective descriptions to try to describe a field of study that does not have its own appropriatte vocabulary does not mean this thing you want to describe as advection is advection.

In just one paragraph they drag in "adjective pore water exchange," adjectively induced," and "advective interfacial fluid" transport." Yet the due not describe what you say as advection.

Once again advection is the picking up and transporting of sediments caused by a horizontal flow of water. The fact that advection transport might mean that this picking up of sediment might extend picking up only 1/4 inch of sediment or 6 inches of sediment does not n matter. The fact that the sediment movement may only 1/4" or 6" or a mile it does not matter.

Yes when there is d advection the water pore water is excahnge by the advection waters but those flows causinf the pore water ehchange are horizontal flows. Yes there is oxygen and nutrient diffusion deeper in the sand bed due to increased water pore exchange so the nutrients and water do not have to diffuse as far.

Your new URL contributers even plainly wrote, "These findings demonsr trate that the classical one-dimensioanl approach ... is inadequate for sandy permeable beds. That is because they are trying to use advection principles in a form they do not apply. Once agian advection is the term and hydrology approach to dealing only with horizontal silt transport caused by horizontal flow.

Therefore once again you are still using the term out of context and trying to excuse that by posting a URL where they are merely inappropraiately trying to use a science or field of study that does not include what they are studying as a part of that study. Advection is a horizontal study no matter how many ways the say that advection tied to their area of study. Trying to use a few parallels between two differing fields of studies does not make them the same nor mean the names, terminology, symbols or even equations are interchangable. Even the same fields within the same science usually approach and call things differently.

I suggest they/you invent new terminolgy to describe something such as the phenomena you are addressing. That is most common in academia. If the phenomena, title, phrase or field of science is different then create new names that are appropriatte, do not use anothers sciences names titles and descriptions inappropriately.

My courses taken are appropriate to the term advection and the study of advection and the use of its many formulas, tables and graphs. I am not wrong in describing advection, you are wrong in thinking yor wrong ful use of advection just because people in the field of marine biology are trying to use it inapprropriately. They even flatly say this approach (advection) does not work in our studies yet they continue to use the language of an approach from another science and even try to extend that inappropriate approachs by using its terminolgy creatively while doing so.

Your argument is moot. Your touted experts and even the new marine biologista are trying to use in a few spots another sciences language improperly. Period. Most of the time their use of advection is done in a manner that supports what I wrote before and waht I write now. At least the German scientists tried to create new more appropriate descriptions such as, "oscillating ing flow, sediment wave ripples, wave induced filtration, wave pumping, unidirectional flow, and oscillating flow." However these are all terms dealing with their science, not hydrogy as it now is. Advection does not include the phenomena you are trying to argue as advection does not cover the area of unidirectional flow or oscillating flow. Period. Vertical flow assisted or even caused in part or made easier by the advection process is either unidirectional flow or flow induced by oscillating flow it is not advection.

You are still wrong and still grasping at straws, and now twisting things back to diffusion it appears. While you may be a intelligent person you are still wrong and obviously outside your field.

Randy is a very smart man and perhaps even qualifies as brillant the field of chemistry. However if he stat rted talking about some other field of study such as hydrology and used terminolgy etc improperly I would have no problem in saying he was wrong and still highly respect him as a chemist. Randy does not often seem to stary much outside of his field of study and when he does he very carefully says it is an opinion or merely based upon his limited knowledge in that area. Boomer is a very bright man and is seldom wrong in what he openly states. He corrects his mistakes. There are researchers in this field of maintaining reef aquariums. Some of there work is good some is not, some works never pass peer review but theu y post it on line or release it in book anyway. Many reaserchers can not bbe readily believe because they scew there research and therefore their data to suit the needs of the people paying for the reserach. Many re top researchers making money in the aquraium trade fields through research, book writing and product endorcements merely use resaerch done by other and expand slightlty on it and thereby profit unfairly by it. When a doctorate student does research and write a paper on that research and has a touted exprt review that paper and then taht touted expert uses that research as a basis for minimal further research and then puts that research result in a book sold to the hobby aquarists that is pretty unethical. Oh well he is still touted by some hobbyists. There are many college Doctorate Professors that receive research grants for reserach and have students do all the work, dat collection, data documentation and calculations and even produce reports or even a thesis on the research, then they publish professional papers on it often giving no credit to the students. Now is that ethical. Randy has never done these things as far as I know, I very much doubt his personal ethics would ever allow it. Neither has Boomer taken credit for the work of others. A book or a dozen books or a degree is not a reason to see a touted expert or two as unquestionable.

I suggest we just quit dealing with this topic and as I said before, 'It is about time." I am done with this discussion with you TMZ. Period!

 

[WaterKeeper]

Gentlemen Please!!!

Argue the facts without personal interjections. Debate is fine but name calling will not be tolerated. If the abuse continues I will close what is an otherwise interesting thread.

 

[tmz]

Tom,

I don't think the are that many facts and they aren't terribly arcane. I'll attempt to summarize and get back on the track :

Terminology:

Advection: predominantly horizontal current and the wave action it produces as it encounters(an) obstruction(s)in it's path as well as the resulting "endo upwelling" under the obstruction. The upwelling occurs directly under the obstruction in a mirror image of it's footprint and height. At a horizontal flow rate of 10cm per second the endo upwelling will occur at a rate of 1cm per hour in the model presented by Sprung and Delbeek. The upwelling also results in water being pulled down .

Sprung and Delbbek use the term advection to describe this phenomenon as do Heutel and Rausch in their research(2). . Esoteric interpretations of discipline specific claims to specific terminology wether they be from engineering, meteorology ,chemistry etc . notwithstanding, I'll stick with them since they represent fields more closely related to reef keeping.

Diffusion: for the purposes of this discussion is the movement of molecules in water toward equilibrium. Some might call this convection but again , I'll use the terminology most commonly used in reef keeping literature.

Nitrification: the aerobic activity of autotrophic bacteria(those that can use inorganic carbon such as bi carbonate and CO2/carbonic acid)in oxic and hypoxic areas to convert decaying material to ammonia and nitrite and coenzymes such as adenosine triphosphate which they uses for energy transfer to enable life functions including cell division.

Denitrification: the anerobic activity of of heterotrphic bacteria(those that need organic carbon for energy) in hypoxic and near anoxic areas to convert nitrate to free nitrogen gas and coenzymes.

Faculative bacteria (those that can use either organic or non organic carbon for energy ) likely also play a role in both nitrification and denitrification.

Applications:

Trickle filters or towers : support high oxygen ,oxic areas and thus produce nitrate as an end product since they do not support heterotrophic bacteria which perish in the presence of oxygen.

Deep sand beds,generally over 4 inches deep as well as live rock can include : oxic , hypoxic and anoxic areas. Both autotrophic and heterotrophic bacteria can flourish in and on them. However, the heterotrophs need a source of organic carbon for energy and coenzme production. The autotrophs do fine with non organic carbon sources. So the deep sand bed needs a supply of organic material(dissolved or undisolved ) to keep the heterotrophs that use the nitrate viable. Obviously, it also needs a supply of nitrate. The bed (or rock) is fed by the water that moves through it via advection and/or the channeling and transport activity of benthic fuana. Diffusion supports the equilibriation of organic carbon molecules and nitrates throughout the water.

A deep sand bed without the proper amount of water movement to bring in the needed organic carbon and nitrate will not function well as a denitrifier. On the other hand too much fluidization will bring in too much oxygen. On the third hand, too much carbon and too little nitrate will set the stage for the bacteria to turn to SO4 for the oxygen they need with the potential for hydrogen sulfide formation as a by product. After that they will move on to metals and other nasty by products.Hence, the caveat on dosing organic carbon when deep sand beds are in play . Although some have suggested seeding a deep bed with sulfur or vodka et al. as a means of sourcing an energy source in a deep bed. I think it's dangerous.

Again a functional deep sand bed needs a force to insure the movement of oxygen depleted water( stripped by autorphic and faculative bacteria)laden with nitrate and a source of organic carbon for the heterotrophic bacteria to thrive and reduce the nitrate .

A bed that is allowed to clog or pack down or is just too deep for things to pass down just wont do very much.Benthic fauna in a live bed can help to maintain viability through channeling activities and assist in transport of organic materials..

Diffusion is a relatively weak force and will not in my opinion provide enough material to promote denitrification.

Advection, can enhance the process multifold( as many as 50 fold see reference (2) putting more water in play in which diffusion can occur.

The study by Tonnen and Wee from the Advanced Aquarist Magazine:
http://www.advancedaquarist.com/2008/8/aafeature3
concludes:

Each sediment-based aquarium design appeared capable of handling nutrient inputs up to 0.5 mg / L / day of NH4+ - which is equivalent to a well-stocked reef aquarium. At this input level, final concentrations of ammonia, nitrite and nitrate did not differ significantly among aquaria 1) with or without plenums, 2) containing deep (9.0 cm) or shallow (2.5cm) sediments, or 3) containing coarse (2.0mm) or fine (0.2mm) mean particle sizes."

So for my money ,deep (9inches or more of sand ) buckets with limited surface area, brisk flow to avoid detritus accumulation and no wave action except perhaps at the perimeter will not denitrify to any significant degree beyond the first few inches if that.

Live deep beds within a display with live rock will do better if the sand is kept live which may require periodic replenishment with fresh live sand..

These beds may also benefit from the effects of advection as the upwelling water passes upward under and through live rock. It seems ensuring sand is under the rock will enhance the process. Issues with the stability of the stack could be handled with pylon pvc structures under the rock backfilled with sand. I have these on my 7 year old in tank deep sand bed.

A remote deep sand bed (ie not in the display) can be more productive in denitrification with a larger surface area since even the small sand grains cause advective wave action and upwelling. Placing live rock on a bed can enhance it's effectivenes as a denitrifier since the effects of advection will enhance water movement under the rock to a depth equal to the height of the submerged rock per the model presented by Sprung and Delbeek.It will also enhance movement of water through the rock.

Nitrate removal can be accomplished by a number of means other than the substratum or rock such as: coil denitrifiers, carbon fed denitriers, sulfur denitrifiers,macroalgae refugia,carbon dosing , the use of granular activated carbon to remove organic material before it turns to nitrate as well as strong skimming and perhaps to some extent ozone in conjunction with granulated activated carbon.

Refernces:

(1)Sprung and Delbeek, The Reef Aquarium Vol 3.
(2)http://aslo.org/lo/toc/vol_48/issue_4/1674.pdf
(3)http://www2.hawaii.edu/~toonen/files/Toonen-Wee-05.pdf

If you'd like to tune this up some feel free , Tom. Your input is always appreciated.

 

[WaterKeeper]

:lol:

It seems all the Chemistry Forum gang are on vacation. I was called in to the discussion just to keep things on a civil basis. Anyway, since I formerly moderated this forum when Randy was on sabbatical I will chime in.

Trickle filters or towers : support high oxygen ,oxic areas and thus produce nitrate as an end product since they do not support heterotrophic bacteria which perish in the presence of oxygen.

You sure you didn't mean obligate anaerobes here. Most heterotrophs handle oxygen very well.

After that they will move on to metals and other nasty by products.Hence, the caveat on dosing organic carbon when deep sand beds are in play . Although some have suggested seeding a deep bed with sulfur or vodka et al. as a means of sourcing an energy source in a deep bed. I think it's dangerous.

The principle post nitrate electron acceptor in water are usually sulfates, which exist in an abundance in seawater. Metals, on the other hand, are at fairly low levels, so fully oxidized iron and manganese would not be a major oxidative source. I've always agreed that the amount of DOM entering a DSB will be a sufficient carbon sink to allow active denitrification. Supplementation should not be required unless the remaining DOM is too refractory for effective electron donation.

A bed that is allowed to clog or pack down or is just too deep for things to pass down just wont do very much.Benthic fauna in a live bed can help to maintain viability through channeling activities and assist in transport of organic materials.

Now there we get to the heart of the matter. Indeed the bio-agitation of a DSB is the key to its success. The movement of of countless ciliated protozoa, burrowing of worms and movement of things like mini starfish is what moves water through the bed. The same organism's respiration also release buoyant gas bubbles that further increase water movement throughout the bed. The bed exists in a state of constant, biologically induced, mechanical agitation and therefore serves as a major detritus processing component to the tank.

I've previously replied about that article by Rob and while I do not reject it I have some doubts about the statements on the bed not being able to process nutrient beyond the first inch or two of sand. My above paragraph explains why I disagree to some extent.