Deep sand bed,to deep sand bed or not to deep sand bed

Hi fellow reefers.
What are the opinions here about the use of deep sand beds?
I have a deep sand bed as the substrate in my 4 foot display tank as advised else where and the next display tank will be fish only,i want it to be a predator tank.
I haven’t had an aquarium with out one so I don’t know if it is doing anything really.
What would you guys say are the pluses and minuses of using a deep sand bed?

The forum users here can be slack, surely some have experience with and with out them to compare and have results to pass on!

This concept began with the plenum style of filtration, the persons name was plenum,it was his idea, this was introduced many years back and the under gravel switched off and the affects of this,the combination of these two brought about the deep sand bed concept!

Personally, I always use similar to the plenum out side of the aquarium, heavily pre filtered before it, it is far better at nitrate reduction and the deeper areas have less chance of becoming a polluting zone.

The plenum style is supposed to have some maintenance, I don’t do it that way and it works fine.

The deep sand bed in the aquarium functions in the same way as when you put mulch in the soil to greater than 12 inches or there abouts,the wrong forms of bacteria develop at the no oxygen levels and you get sulphur and other nasties in abundance leaching into the air, and in the aquariums waters, these are water soluble and enter your corals and fish when they drink, then you get sickfish,sickend corals and PH all over the place in time.

The health of your aquariums life starts to suffer a little and you need to buy more support gear and buy more corals, more fish and more water changes, this is a slow but certain loss in water quality from in tank deep sand beds because the bones in the fish food, the silica from shrimp shells, dead algae formation structure, the worm track walls, bacterium formations, all these block the porus aspect of the in tank deep sand bed and you now have the same as the mulch to deep in the soil!

Deep sand beds initially provide heaps of calcium,strontium,magnesium as the acidic environment the anaerobic bacterium creates dissolves some of the deep sand beds calcium particles/granules that make it up,normally,then of course if they consist of other types of particles,as the dissolving bacteria builds, that can be an even bigger issue!

In the early days the first third of the deep sand bed is an efficient aerobic environment, with in a month or so the next two thirds consist of powering anaerobic bacterium and alls good.

As the bed becomes permeated with blocking particles and life forms, the first eighth is now aerobic and the next two eighths is anaerobic and the rest is leaching polluting gases into the aquariums waters!

Also if you disturb an in tank old deep sand bed, like a year or more aged, the life forms and substances in the bed below the aerobic and anaerobic bacteriums,once these make contact with rich oxygen waters, will normally screw up your PH and set off chain reactions killing every form of life in the aquarium, very quickly!!!!

Any substrates of any description in the display tank will be a problem to the aquariums longevity, one way or another, this is inevitable.

Here is some info I have read from elseware - is also based on my old school approach which I must say was quite successful with most marine life forms...

For what its worth -please note this is simply another experience and perspective comparativley that may help you understand......

The limitations and potential pitfalls of employing a DSB's are far less mysterious or unpredictable than previously thought. In fact, deep sand bed methodologies now have a history of more than 20 years in use and may fairly claim to be regarded as "tried and true". Your first decision to make on contemplation of the strategy is purpose. Although you will likely enjoy a combination of benefits with any interpretation of the strategy, some methods are more effective than others in various aspects. Choose from the above described potential benefits and focus on which ones suit you best: aesthetics, nitrate control, or plankton production to begin with. If your purpose for using sand (in contrast to course gravel, shell forms or nothing at all) is only aesthetic, you may wish to forego very deep beds altogether and enjoy a shallow substrate (less then 1"/25 mm) with little regard for sand grain size; there are few benefits or risks in doing so. Nitrate control, instead, is best achieved with sugar fine sand. Zooplankton production (amphipods) to feed fishes may require more coarse sand. And coral propagation (active "fragging" by the aquarist) will often demand a dressing of rubble atop any substrate for a faster settlement of clones and divisions.

After an introduction to the merits of deep sand beds and the "living substrates" you might ask yourself, "what really is live sand?" Live sand is essentially a combination of non-living substrate (usually calcareous in composition but it can be silica-based) with a myriad of tiny beneficial life forms infused throughout it. There are beneficial organisms living on (meiofauna) and between (infauna) the substrate. Creatures found in this medium range from visible zooplankton down to a wide range of microbes dominated by bacteria. Indeed, live sand is much more than microbial colonies battling it out for space and nutrients. All phyla of marine life have representation in sand on the living reef. Some of the most commonly encountered organisms are segmented worms (annelids), roundworms (nematodes), micro-crustaceans (amphipods, copepods, mysids and the like), and bivalves (mollusks), but there are many, many more organisms in tow.

By the activities of live sand organisms, a DSB imports many nutrients, export others, and serves as an extremely efficient living "filter" at large. Space and food are exploited by the colonization and proliferation of crucial microorganisms. Other undesirable elements from the water are simply precipitated and bound into the substrate. Live sand certainly is a complicated and fascinating microscopic world of its own, and quite worthy of a closer look... so get that magnifying glass or microscope out! There is a veritable microscopic zoo to browse.

Plenum Or No?

Since the popularization (and misapplication) of the Jaubert-style plenum for deep sand bed methodologies in the early 1990's, much has been written, debated and revealed about the use of this feature. For those of you new to the issue, rest assured that there is little you truly need to know as a casual aquarist. A plenum is a physical water space underneath a deep bed of sand. It is used to create a hidden, dead space of static water to facilitate the diffusion of nutrients and other vital components of biological processes through the substrate. The premise here is that the biological faculties we seek to harness for natural filtration in live sand can be supported and encouraged by this feature. In the bigger picture, this may indeed true. Some of the challenges of employing this technology in the past were understanding and adapting it from the original recommendations that trickled into popular aquarium literature. It seems that at least some of the early systems incorporating this strategy were very large semi-closed or open systems (fresh flowing seawater) with extraordinary depths of sand that cannot easily be incorporated by home aquarists. Without getting too involved in the "how's" and "why's" of the matter, let us summarize that the plenum methodology has not been demonstrated to be exceedingly useful or particularly harmful. Most aquarists find that there is little difference with or without a plenum for a deep static bed of sand in a healthy home aquarium system. This should bear no reflection on the validity of the methodology, but rather illuminates that the adaptation for home aquarists, especially with smaller aquaria, may have little impact. Admittedly, there are no hard and fast rules here. You may have an interest to experiment with the strategy and are encouraged if so. Just know that having a plenum is not critical to success with deep sand bed methodologies.

One last mention of the improper implementation of plenum and deep sand bed strategies collectively. We should like to dispel the most common corruption of the application for those interested to know or try it. Severe criticism of their use has faulted them for becoming "nutrient sinks": trapping and accumulating detritus to levels that cripple water quality and fuel nuisance algae growths. The reality of the matter may likely be that an incorrect application of the technology caused the rift. As aquarists, we too often have inadequate water flow, which prevents detritus and organic particulates from being properly exported by protein skimming and other filtration dynamics. In turn, excess detritus settles in pockets and migrates deep into the substrate. Furthermore, course sand and gravel is still quite popular and allows particulates to settle and accumulate rather easily. The killing blow to a flawed application with course substrates in weakly circulated aquarium is the unfortunately popular employment of intermediate depths of sand at 1"-3" (25-75mm). In this mid range, the sand is often too deep to be wholly aerobic and yet not deep enough for efficient denitrifying faculties. As such, the two dominant (and desired!) biological populations are restricted if not excluded at large and the sand bed may become a dead zone... a nutrient sink. However, intermediate sand depths can be maintained successfully (often, in fact!), but require due diligence with regular sifting naturally or mechanically (by the aquarist or by creatures in the aquarium), strong water flow in the tank, realistic bio-loads, etc.

Interesting read, but is inherit of a lot of information from the net.

The plenum is a very old style of filtration; its origins go back further than the name Jaubert!

This idea was floating around in the early eighties and I herd back then well before that as well, but I was still using reverse flow under gravels back than in my storage tanks,I tried it for some years later though, not the display tank though after the live rock phase we went through, the display tank was much more advanced for on going experimenting on ideas and herd about or read about styles of filtrations.

The basic principals are the same in many ways over all as to how life exists in a bed of sand with in the aquariums waters, just how it works at what depths, and with what rubbish you allow into it or how much time you spend on it with maintenance, that’s where every one falls down on them normally!

The thing is with lots of live rock in the tank to supposedly run most of your nitrite cycle oxidises you have now covered a large part of the sand bed, there is no way to clean under there with out moving the live rock, if you do there goes your PH stability for an hour or a month, they are all different in how they stuff up.

I even tried a way to resolve that issue,build a sealed raised glass floor of half the tank and 60 mill high for the live rock to sit on with a couple of mill of shell grit on it,the other front half of the tank was to the bottom of the tank,just another experiment!

Plus when and if you do siphon off the bed,as you should once a week, the planktonic life forms that do live in there and multiply, some get sucked out upon cleaning, that is if the zoos have phytos to feed on,you see on average plankton leaves the bed and live rock to feed after lights out, how many of you continue feeding at regular intervals after lights out of foods the varied plankton can feed upon, dosing pumps do not like to handle fresh foods and not all plankton are going to fossick on rubbish that gets into the bed!!

There is no way you can affectively maintain a deep sand bed to enhance its best out comes in the display tank it self!

So out side of the tank, the maintenance prob is gone.