Live Sand Filtration  :
--------------------------
Albert J. Thiel

A little over two years ago, hobbyists here in the United States 
started to experiment again with the addition of  substrates to 
their reef aquariums. This "rediscovered", but certainly not new, 
filtration technique was now based on the methods described by Fossa 
and Nilsen in their books and also on the practices employed by Dr. 
Jaubert of the Monaco Aquarium. This is clearly in opposition to 
previous methods in vogue that all advocated the use of crushed 
coral or, alternatively, dolomite. Fossa, Nilsen and Jaubert 
strongly recommend the use of aragonite, oolitic sands and other 
forms of calcium carbonate.

What has become apparent here in the US is that most hobbyists do 
not really set up "true" live sand systems such as the ones 
mentioned above, but resort to a set-up that is a mixture of those 
methods (a hybrid system). This is because many of those switc hing 
to Live Sand filtration already have aquariums and are, in essence, 
merely converting their existing tanks (that already contain live 
rock) by adding live sand as an additional means of filtration.

It is not quite clear from the available texts where the use of such 
substrates began first, whether it was in Denmark or in the 
Principality of Monaco. One thing is sure though, the Monaco method 
was patented by Dr. Jaubert and little in depth information is 
available about it. Even the videos produced to illustrate the 
method seem to by-pass the more important technical details and just 
show "general" views of  his systems. Unfortunate indeed.

The use of "substrates" in aquariums can hardly be called innovative 
as hobbyists around the world had been experimenting with such 
techniques for years and years. I must add that these attempts did 
not meet with a great deal of success because said techniques were 
not refined and stable. The types of substrates used were also not 
of the kind now in vogue and recommended by Fossa, Nilsen, Jaubert 
and leading aquarists in the US who have experimented with several 
types. Andy Hipkiss, of the UK, has implemented the US method and 
reports excellent success with his Live Sand and Live Rock aquarium.

The contributions of Fossa, Nilsen and Jaubert resolved, once and 
for all, what these substrates should be and how the technique could 
be safely implemented in closed systems such as our aquariums.

Methodology refinements are still being made to this date and 
discussions are still going on about how to construct the substrate 
layers, and what materials to use to be really successful. This 
article attempts to give you a short overview of the most practiced 
methods and what substrates are, in fact, being incorporated in the 
setups that are now successfully in use. It also shows you 
graphically how to set a live sand filter up.

1. Filtration with a Plenum:

The Plenum, or the void space below the layers of substrate used in 
the Live Sand method, should be around one inch. Water obviously 
fills this space. Substrate particles are prevented from entering it 
by using "screens" that do not let it through.

Since the oxygen content in the tank's water will be higher than 
that of the water underneath the substrate layers, and since oxygen 
tends to want to diffuse evenly throughout the water at the same 
time, a small amount of current will occur from the tank to the 
Plenum. This ensures the supply of small amounts of oxygen the 
lifeforms in the substrates need and ensures the growth and 
proliferation of the bacteria present.

To understand how this type of live sand filtration is set up it is 
best to refer to the drawing that illustrates the various parts. 
They are clearly marked and the thickness of the layers is 
indicated. These are suggested numbers, not absolute numbers. They 
represent what the average hobbyist may want to use as a guideline. 
They are not to be considered numbers you must adhere to. You do 
have some flexibility in terms of how much of each you use. The key 
factor though is the composition of the materials used:

- the bottom layer is made up of crushed coral and crushed shells
- the top layer is made up of fine aragonite or oolite (forms of 
calcium carbonate)

The two layers are separated by mesh to prevent them from mixing up. 
The finer the sand the finer the mesh needs to be used.

Obviously, as you may have surmised, when installing thick layers 
you will need a rather deep tank or not much space for water, rock 
and animals will be left. Keep this in mind when selecting a tank or 
you will be disappointed after setting it up and suddenly noticing 
the little amount of space left.

What is done here in the US is as follows:

- the bottom plate to create the Plenum is a piece of so-called 
white eggcrate material (often used to shield fluorescent tubes) 
that is cut to size and supported in as many areas as possible with 
solid rod or squares of plastic or a similar salt water resistant 
and safe material. The weight of the rock and the substrate layers 
require this. The larger the tank the more supports will be 
necessary. Use solid supports to prevent water from entering the 
inside of hollow ones and stagnate there.

Refer to the drawing for the thickness of the layers you need to 
use. Layer 1 needs to be made up of a mixture of crushed coral and 
crushed seashells. Layer 2 needs to be made up of very fine sand. 
You should start the system up with at least some live sand in it. 
You can, however, as is done in the US, mix live and non-live sand. 
Over time the non-live sand will become live as animals migrate from 
the live sand and the rocks to the sand substrate. This usually 
takes a few months for it to happen.

Whether the whole tank bottom is covered with live sand is not all 
that critical. Many here only fill a portion of the tank with it 
(e.g. the front few inches).

A top view of such a set up is illustrated as well

2. Live Sand Filter without a Plenum :

In this particular case live sand is not covering the entire area of 
the tank. Often what is done here is that Live Rock is placed in the 
back of the tank and the sand in the front (see drawing). The sand 
can be separated from the rock with a piece of acrylic to prevent 
it from moving all the way underneath the rocks towards the back of 
the tank. Yet another method practiced is to place the Live Rock 
itself on eggcrate to keep it off the bottom although not everyone 
does so. This allows for easy cleaning underneath the rock.

Without a Plenum the Live Sand is placed right on the bottom of the 
tank. This creates potential problems of anaerobic activity if the 
sand is not populated by a large amount of animalcules that keep it 
in constant motion. Some fish and small herbivorous crabs can help 
this movement as well.

Whenever setting up a tank using this method you need to ensure that 
the sand is live and add some additional animals to the tank 
yourself, animals know to dig into the sand and keep it stirred up 
so small amounts of oxygen are always present. The sand layer can 
be anoxic or hypoxic but not anaerobic. Refer to the diagram for a 
better idea on what this may look like and what the materials used 
are in this type of arrangement.


Live Sand Filtration is not new but it is not as widely practised as 
one imagines. Even here in the US only hobbyist who have been 
keeping reef aquariums for longer periods of time are experimenting 
with it and are reporting excellent results in terms of water 
quality and improvements in coral appearance and growth.



Live Sand Filtration Trends in the USA (Part 2)

As explained in Part 1 of this article, very few hobbyists actually 
set up  full-fledged "Jaubert" systems (according to the method 
described in Part 1, including the so-called Plenum, or void space, 
underneath the layers of crushed coral and live sand) because they 
already own an operating aquarium and, for obvious reasons, do not 
wish to break this tank down. Few, indeed, take existing aquariums 
apart and start completely anew implementing all of the Jaubert 
method's features. Most hobbyists "add on" to their existing 
filtration system and, in essence, run what can be referred to as a 
"hybrid" system, combining parts of the Jaubert method with part of 
the Berlin method.

The existing filtration in such operating tanks is often a live rock 
system (Berlin Method) with, perhaps, a trickle filter as a part of 
it, a trickle filter from which the biological media has been 
removed, as this is what is recommended as the modus operandi for 
the Berlin Method here in the USA. Strong protein skimming 
supplements this type of set up. If it does not, it should (as 
explained in the article on foam fractionation in an earlier issue 
of this magazine). Strong protein skimming IS necessary to keep the 
aquarium water at the desired water quality parameters (see article 
on foam fractionation). Without foam fractionators pollutants will 
build up in concentration and will lower the water quality in a real 
short period of time.

Since most hobbyists use the "hybrid" method of setting up live sand 
aquariums, I will cover this method in more detail in this article. 
In fact, I hope that by the time you are through reading this, you 
will be tempted enough to set one up yourself.

What are the main benefits of live sand aquariums vs. other types of 
filtration methods?

- Greater skimming efficiency due to the use of much more powerful 
foam fractionators, resulting in higher water quality levels 
(typically higher ORP and higher dissolved oxygen concentrations).

- Nitrate reduction to inert materials in the sand and in the live rock.
- Enhanced biological filtration.

- Low or lower ortho-phosphate concentrations thanks to the addition 
of limewater to the system. Limewater precipitates PO4 out of 
solution. In most live sand and live rock tanks the ortho-phosphate 
concentration eventually drops so low that no test available will 
measure it, not even those tests that read in the real low ranges, 
for instance 0.02 ppm.

- Increased nutrient recycling, making some of them re-available to 
the corals before these nutrients are removed from the system.

- Less incidence of disease due to the "pseudo" antibiotic quality 
of live rock and live sand exudates.

- Higher reduction oxidation levels without the use of ozone or 
other artificial methods to raise it, like permanganates.

- Far less dissolved organic material due to the use of high 
efficiency venturi or similar type skimmers.

- Less or no nitrates in the system thanks to the denitrification 
going on in the live rock and in the live sand itself.  This, by 
itself, is a major advantage of this kind of a filtration system.

I could, in fact, go on and on about these benefits. Live sand and 
live rock combination aquariums simply result in overall healthier 
systems in which all animals look at their best and live much longer.

Back to our "hybrid" system though, and what the hobbyist needs to 
do to set up such a system successfully and without too many 
difficulties. It should be understood that this article assumes that 
you already operate an aquarium and that this aquarium contains 
"cured" live rock (probably in the vicinity of 1.5 to 2 pounds of 
live rock per gallon of water in the system, which means the tank 
and the sump if any is present).

Before any live sand is added or can be added the aquarium needs to 
undergo a few changes. Indeed, space has to be made for the live 
sand. This is done by clearing an area in the front part of the tank 
by moving live rock out of the way. It can usually be placed higher 
up in the aquarium or, if that is not possible it may have to be 
removed from the tank altogether. What you want to end up with in 
the front of the tank is a bare area that is about 6 inches deep 
(front to back) and runs the whole width of the aquarium. This is 
the area where the live sand will be placed.

To hold the live sand in place though, a dam has to be inserted in 
front of the live rock. The easiest way, in my experience, to do so 
is to use a long piece of thin acrylic that is the same width as the 
tank and about 5 inches tall. The thickness does not really matter 
all that much as it will be butted against the live rock and will 
remain in place. I have used very thin acrylic and thick one and 
there is no difference what so ever in terms of how well it hold the 
sand in place as long as the acrylic is butted up against the rock 
that is right behind it.

What you now have is an aquarium filled with live rock in the back 
and an empty space in the front of the aquarium. The two are 
separated by the piece of acrylic which I called the dam (or a 
similar material that is saltwater safe).

Note that the bottom part of the acrylic separator needs to be 
rounded off a little to account for the silicone elevation at both 
ends of the tank. If you do not round it off you will not be able to 
position the separator completely on the bottom. Use a regular file 
to round the acrylic off. If you do not round off the ends, sand 
will migrate to the back by going underneath the dam.

Now that everything is in place, you are ready to add the live sand 
to the tank. Hopefully you have ordered from a real good source 
ensuring that the live sand is truly "live". To this live sand you 
will want to add, what I call, diggers and dwellers.

"Diggers" are animals that bury themselves in the sand and keep it 
stirred and moving around, "dwellers" are animals that live on top 
of the sand and eat the detritus and other food forms that may 
collect out of the sand (note that "food" is taken here in its 
widest significance; the sand is passed through their body while 
bacteria and small food particles are removed in the process, a 
typical behavior of Sea Cucumbers feedings _Holothuria_ sp.).

Examples of diggers include sea cucumbers, small burrowing snails, 
some fish that dig in and out of the sand, sand worms and so on. 
Dwellers are mostly herbivorous or detrivorous small hermit crabs 
and bottom dwelling fishes such as Mandarin fish, some Gobies and 
some small Wrasse. Most suppliers of live sand also sell the diggers 
and dwellers (at least here in the US).

When the sand arrives you will need to add it to the tank slowly and 
try to lower the bag, in which it came, to the bottom of the tank, 
slowly emptying it in the areas in front of the divider. This will 
minimize the cloudiness that develops and will ensure that the life 
forms stay in the sand. Do not pay too much attention at this point 
to even it out. You can do so later.

How much sand do you need? There happens to be a formula used here 
in the USA to calculate the amount of live sand needed. Take the 
width in inches times the height in inches times the length in 
inches and divide that number by 23.5 (measurements of the area you 
need to fill). That will be real close to the amount of live sand, 
in pounds, you will need to fill up the space you had in mind. This 
formula is derived from the average weight of live sand and the 
calculations used to determine the volume of an area. The formula is 
somewhat of an approximation as not all types of sand weigh the same 
(the finer the sand is the more it will weigh per given volume).

What sand should you use? Over here we like to use aragonitic sand 
(a form of crystallization of calcium carbonate but some hobbyists 
use silica sand as well). The former is, in my opinion, better. The 
latter may give rise to the appearance of diatom algae. Diatoms can 
be removed and eliminated completely by using silicate removing 
compounds in the tank's filtration system. Such compounds are 
available commercially even in the UK.

Another type of sand that can be used, and which I believe is 
available in the UK, is "oolitic" sand, yet another crystallization 
form of calcium carbonate.

Personally I do not care specifically for sand that is "real fine". 
Hobbyists here in the USA have had success with it though, and it 
certainly is a substrate to consider if you are adding live sand to 
your tank. At this time, to my knowledge, no one has come up with 
real good reasons why finer sand seems to work better but, no doubt, 
as time goes on, someone will. As long as the sand is live and fine 
it will work for you. It does, in my opinion, not have to be "very 
very fine".

Some suggest that one should not use silica-based sand (as I 
indicated earlier) for fear of diatom outbreaks (use a silicate 
removing compound if diatoms appear). Others are convinced that only 
aragonitic or oolitic sand can be used. All I can say in this 
respect, at this point, is that the final word on this matter is not 
out yet and that the tanks I have set up using the various types of 
live sand mentioned have all given me excellent results. I certainly 
have not run into the problems described by some.

I strongly believe that these problems stem more from not curing and 
aging the tank for long enough rather than from the type of live 
sand used.

Once you have placed the sand in the aquarium, you can even it out 
somewhat and place your diggers and dwellers in the tank. It does 
not matter where you place them. Just put them on the sand and they 
will find their own favorite spots and start roaming around.

That is basically really all there is to it. Your hybrid system is 
now set up. Remove all filtration from the tank except for the 
skimmer (upgrade to a larger model if necessary as skimming is the 
most important part of this type of a system). Note that in these 
systems no mechanical filtration is used. Strong currents in the 
tank keep detritus from settling and covering the rocks and the 
sand. The skimmer removes some of it and omnivores added to the tank 
take care of the rest. Recycling of nutrients after they have 
mineralized also removes some of them. This mineralization occurs in 
the live rock and in the sand. That is, in reality, why this method 
has gained popularity. What had to be achieved previously "outside": 
the tank can now be brought about "inside" the aquarium. I, and 
others, consider this a major step forward in the operating of reef 
aquariums.

As days go by you will notice that all conditions in the tank 
improve and that all animals seem to like their new environment much 
better, evidenced by the manner in which they react to the water 
quality and their improved appearance. That is my experience with 
several tanks set up in this matter, the smallest one being a 20 
gallon US long type tank (Live Sand and Berlin Method hybrid 
aquariums do not have to be large as some may think).

Hopefully I have clarified this method for you. If you have any 
further questions though, do not hesitate to write to me care of the 
magazine. I will be pleased to deal with whatever topics you need 
clarified.

Next month we will deal with the Jaubert method more in detail, 
including how to set up the tank with a plenum and how to go about 
starting it from scratch.


Albert J. Thiel
June 1995