ISSUE # 4 page 2 APRIL 1997

THE NATURAL REEF

For the truly avid marine as well as freshwater aquarist there is not a better accomplishment than to get a specimen to reproduce, for most of the time the only organisms that reproduce constantly are the organisms that we do not desire, like micro algae and the aptaisia(rock anemones).

I myself started like many others with fresh water tanks and the usual tropical fish ie. platties, guppies, and the like. It has been long since that time, but, I can never forget the morning when I found that my platties had bred, since then I have moved toward more and more difficult organisms, with the ultimate challenge, salt water organisms.

I'd like to give you a brief but incomplete description of a simple low maintenance system and ecologically sound salt water breeding system with emphasis on ease of running and maintenance. There are many different schools of thought on how to set up a salt water aquarium system like the Berlin style, the Lee Chin Eng, Reverse photosynthesis, Algae scrubbers and others, I believe that none of these systems is the total solution to the problem.

The goal of almost every marine aquarist is to recreate a portion of our wonderful ocean. So for the solution to this problem we need to look at the very same system that we are trying to recreate, the oceans, and not only from the point of view of aesthetics, but, from the point of view of the marine life chain and the interfaces among all of its components, from the micro fauna and micro flora to the macro fauna and macro flora. Almost every one of the schools of thought only considers the macro fauna and only very few consider macro flora and almost none consider micro fauna or micro flora.

The system that I use incorporates parts of all the common thoughts with emphasis on micro fauna, micro flora, and macro flora to accomplish a faximile as close as possible to the real system (the oceans).

A common goal for most aquarist is to keep a clean tank, for most of us this means a sterile environment, for this reason we use all sort of equipment, for the most part, expensive, to remove in one way or another, almost everything that is in the system. I will try to point out some of the pitfalls of the most common pieces of equipment used in the maintenance of our systems.

I will begin with the commonly called Protein skimmer or foam fractionation device. The protein skimmer is a very efficient piece of equipment. The skimming process consists of the injection of very fine bubbles of air into a column of water. The size of the bubbles are so small that any material suspended or dissolved in the water gets removed. The most frequently removed substances are, amino acids, organic dyes, fatty acids, fats, enzymes, vitamins and many inorganic compounds like phosphorous and iodine.

The main draw back to this piece of equipment is that it cannot differentiate between desirable and undesirable substances, thus removing most matter from the water. The most important components of the water column that gets removed are the micro algae, and micro fauna that forms the plankton and serves as source of food many of our organisms that we are trying to maintain.

Another piece of equipment that is almost always used is the Wet/Dry filter. The Wet/Dry filter consists of two sections, the first houses an amount of filter media where the water trickles through so giving it one of it names "Trickle Filters," and the second houses filter media that is permanencly submerged in the water. This trickling of the water through the filter media exposes the water to a large amount of air, aiding in the removal of CO2. The removal of CO2 from the water aids in keeping the PH high and the large surface area of the filter media houses a large colony of bacteria.

Bacteria related to the genus nitrosomonas, use ammonia(NH3) as food producing nitrites (NO2-) as a by-product. Nitrites are as toxic as ammonia themselves. The second type of bacteria is related to the genus nitrobacter, these bacteria use nitrites as a food source, it breaks down nitrites and produces nitrates (NO3-3) "Fertilizer" as a by-product.

Nitrate is relatively nontoxic to most organisms in low concentrations, for the nitrates to be reduced into free nitrogen gas (N2), an almost anaerobic area is required. The wet/dry filter does not provide this type of environment needed to grow the necessary bacteria, and this gives another name to this filter "The nitrate factory." The nitrogen compound, nitrate, is readily used by micro algae, sometimes leading to micro algae booms, due to the increased amount of nitrates "fertilizer" in the water.

Ozone is the most powerful oxidant readily available for water treatment. It is used by injecting it into the water. This is normally done in a chamber commonly known as an ozone reactor, but most commonly it is injected into a protein skimmer directly. Before the treated water is returned to the aquarium it must be passed through an ozone destruction device, such as a UV light of activated charcoal. The water treated has to have all ozone removed from it. This is very important in order to prevent burns in the gills of fishes, and delicate membranes of other organisms.

Ozone is a "non selective" oxidizer that can eliminate bacteria, viruses, iron, manganese, hydrogen sulfide, taste, and color. If someone is exposed to ozone it can cause burns to the skin and more dangerous burns in the lungs if it is aspirated. Ozone is at least a 50% stronger oxidizer than chlorine. The advantage of using ozone is when it is oxidized it reverts to oxygen. Ozone is very unstable, it will revert to oxygen within about an hour, even if there are no organics for it to oxidize.

As it can be seen by its description, the use of ozone for the treatment of aquarium water is an overkill measure that destroys most the eggs and larvae of the many organisms that make up plankton. Most of these larvae and eggs are from the very organisms that we are trying to maintain and most of the rest are organisms that serve as food for our organisms. Only a small portion of the organisms suspended in the water are undesirable in our system, this does not justify the use of ozone in our systems.

The ultraviolet sterilizer is another piece of equipment that is very efficient in the removal of bacteria, algae, fungi, and organic compounds. These compound can be part of an organism or dissolved directly into the water. This sterilizer uses ultraviolet radiation in the range of 254 nm. Ultraviolet radiation is able to break the molecular bonds of many biochemical compounds including DNA.

Now I would like to discuss some methods that I use in my system.

In most healthy coral reefs the amount of dissolved nutrients is small. The size of the different populations is controlled by how much food is available to each population. In a typical aquarium there is not a balance between producers and consumers. For the most part nutrients (ammonia, nitrites, and nitrates) are produced faster than they can be consumed leading to a rapid accumulation of these nutrients in the system, to the point where they can reach dangerous level.

In nature nutrients are either used to produce energy or stored as tissue build up, nitrogen in most of its forms (urea, ammonia, nitrites, and nitrates), phosphates, and potassium are some of the main nutrients for plants. Plants utilize these materials to produce energy and to build tissue.

In most of the systems that aquarist maintain the amount of plant material is minimal or none, all these systems rely on biological processes to get rid off these unwanted materials. By the introduction of plant material into our systems we solved this problem. The uptake of these nutrients by the plant material is much faster than the conventional biological processes, so decreasing the accumulations of these nutrients in the water column. The uptake of nutrients by higher algae is relatively fast, but not fast enough, in comparison to the lower algae. Lower algae like hair algae, which nobody wants. This leads to hair algae grow even when there are higher algas present in the system.

The solution is to designate a specific area where these "undesirable" algae can grow. This leads to what is commonly called Alga Scrubber. The fast growing algae of the scrubber can easily cope with any sudden shift of the amount of nutrients in the water by changing its rate of growth. Direct removal of nutrients is achieved by the removal "harvesting" of algae from the scrubber. This alga is dried and then made into powder and used as a food supplement for various organisms in the system, therefore completing the cycle.

During the time that the algae are exposed to light, oxygen is produced as a byproduct of the photosynthesis process and CO2 is consumed, this removal of CO2 from the water causes the PH to rise. One common consequence of this process is that when the algae are not exposed to light the production of oxygen is reduced and the production of CO2 is increased.

This increase of CO2 leads to a decrease of PH during the periods of darkness. Many fragile eggs and larvae cannot cope with these drastic PH fluctuations. These drastic fluctuations can be eliminated to a great extent by lighting the scrubber in an opposite cycle than the main tanks this eliminates the PH fluctuations and maintains the amount of dissolved oxygen constant in the water. This is known as reverse photosynthesis.

The common nutrients like ammonia, nitrites, nitrates are close to the end of the chain of detritus transformation. In most of our systems, detritus produced by the higher organisms are left to the bacteria to break into the smaller compounds, this process is relatively slow.

There is not a perfect digestive system in nature, almost all the waste that is produced by the organisms in our system contains large amounts of "uneaten" food. This food can be used by smaller organisms, the transformation done by these organisms is much faster than if it is left to the microbes alone.

These processes are relatively simple given the presence of the appropriate organisms. This is not so in most of our systems. The continuous use of equipment that removes these organisms and its offspring causes an accumulation of detritus. This detritus is left to microbes to transform, the rate of accumulation is greater than the rate of transformation, leading to many of the problems that we have already mentioned.

In my system, the readings of ammonia, nitrites and nitrates are undetectable by the conventional methods of testing. I think the alga scrubber provides an optimum environment for the reproduction of many organisms that form plankton and this is an extra advantage.

Another issue of concern for every aquarist is the replenishment of substances consumed during the various biological processes that takes place in our reef systems. One of the most important substances that we have to be concerned about is calcium. Calcium is used by almost every organism for the building of their skeleton.

Many methods are used for the replacement of the consumed calcium. The most widely used is the addition calcium hydroxide solution Ca(HO)2 commonly known as kalkwaser. Calcium hydroxide solution is extremely caustic, and it has to be added to the system very slowly to prevent rapid PH changes that are detrimental to many organisms.

In my system I do not use kalkwaser , I use the live sand system in combination with a plenum. A plenum is a barrier between the gravel and the bottom the tank, normally 1" off the bottom, this is followed by 3" to 4" of aragonite gravel, with time this gravel becomes a biological filter. The heavy biological activity in the gravel causes a depletion of oxygen in the lower section of the gravel.

This has two different benefits. The first benefit is that the depletion of oxygen in the lower section of the gravel and the area underneath the plenum creates an almost anaerobic area. This area provides ideal conditions for the proliferation of bacteria that converts nitrates into free nitrogen gas N2. The second benefit is that due to the heavy biological activity within the lower sections of the substrate the PH of the water in this section is lower than the rest of the water. This lowering of the PH causes the substrate to dissolve slowly releasing its components into the water column. This maintains a constant amount of calcium dissolved in the water.

In my system the calcium level is maintained between 480mg/l and 500mg/l, without the addition of kalkwaser or calcium chloride and the alkalinity 10 to 12 dKH without any carbonated precipitate.

The issue of the collection of detritus in the gravel is taken care by the presence of large community of micro crustaceans and worms ie: mysis shrimp, grammarus, and spaghetti worms. These organisms are allowed to reproduce without the presence of major predators. The occasional feeding of micro algae and rotifers is very helpful.

I hope that what you have read has inspired you into thinking about our aquarium systems more as a complete biological cycle and less as just show pieces. As we all know, nature does not use any equipment for the "cleaning" of its water. In nature all the parameters are kept in balance, only when this balance is broken do problems arise. A natural system provides a healthy environment with reduced maintenance.

Click on the banner to vist Aquarium Systems, Inc.

Building a reef plug mold for making aragacrete reef plugs.

1 piece 2" x 12" lumber 24" long.

TOOLS:

Drill press or hand drill
1/2" wood bit
1 1/4" step bit - this bit is shaped like a sander cone with 1/8" steps.

INSTRUCTIONS:

Lay out the 2" x 12" board with holes 1" apart.
Drill pilot holes on each center mark.
Finish the holes with step bit.
Be certain the holes go all the way thru the mold.
Sand the mold smooth with 220 grit sand paper.

These molds can be made any size that easy to work with. Use wood that can be soaked such as fir or clear pine. A drill press is the best tool for the job. A hand drill can be used, but a simple drill guide will help you make the holes square with the mold.

MAKING REEF PLUGS:

MATERIALS:

Carib Sea^TM aragonite sand.
#3 portland cement

INSTRUCTIONS:

Presoak the mold in water for 1 hour.
Mix 5 parts Carib Sea^TM aragonite sand with 1 part portland cement.
Set the mold on a smooth surface and pour in 1/2 tablespoon dry aragonite into each hole.
Pour the aragacrete into each hole in the mold.
Let the aragacrete set for 24 hours before you push the reef plugs out.
Soak the reef plugs in white vinagar for 12 hours and rinse them in fresh water before you use them.

LOW COST BULLET PROOF REEF AQUARIUM Learn to start an inexpensive reef aquarium
55 GALLON INSTA REEF Visit Rachel Read's 12 week old Bullet Proof Reef Aquarium
MORE PICTURES OF THIS REEF AQUARIUM

Image Page for Zoanthids and Palythoa