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When it's time to purchase the equipment for your new tank, the first decision you will have to make is whether you will be setting up a fish-only tank or a mini-reef. A fish-only tank is basically self-explanatory: a tank with a single specimen or a community of compatible marine specimens. A mini-reef contains mostly coral (hard and soft), sponges, anemones, and other sessile invertebrates. Fish can be included in a mini-reef, but usually only a small number. Because of their demanding nature and difficult parameters, mini-reef aquariums are not recommended as first-time tanks, and they are usually only kept by mature hobbyists. This article will list suggested equipment for a fish-only tank.


A fish tank should be made of either glass or acrylic. Glass tanks come in a wide range of sizes and shapes, and they are fairly inexpensive. Also, tanks made of glass are almost completely scratch resistant. However, glass tanks are very heavy and can potentially shatter or spring leaks. Acrylic tanks are extremely resistant to shattering, but they are easily scratched. They tend to be more expensive than glass tanks, but acrylic tanks also provide a superior view with less distortion because they allow more light to enter the tank.

When purchasing a tank, a good rule of thumb is “the bigger, the better.” A larger tank is generally easier to maintain than a smaller tank, because any changes in the water or tank residents will be less dramatic the more water is involved, which will give you a better chance of solving any problem before it gets out of control. When deciding what size tank to purchase, consider how much space is available in your home and how much weight your floors can support. A 55-gallon tank is a great size for a beginner saltwater tank.


A fish tank will require a stand to keep it off the floor and put it at a height that allows easy viewing and access. Stands made out of iron or metal are not recommended for a saltwater aquarium, as they will quickly rust when they come into contact with salt water. A stand made of wood or acrylic will last much longer. Although it is possible to build your own stand, the stability of a tank stand is extremely important, so a task like that is best left to a master craftsman. A commercially-made stand that is sized to fit your aquarium is a great option.


While a substrate is not required in a saltwater tank, and some experts say that it will only trap waste and cause the nitrate level to rise, it does provide a certain esthetic appeal. If you decide to use a substrate in your tank, choose from crushed coral, dolomite, or aragonite gravel. If you’re not using an undergravel filter, fine-grain sand is another option. Do not use the colored variety of gravel that is popular in the freshwater hobby, as it lacks the buffering capacity of marine substrates, and it does not have the look naturally associated with saltwater aquariums.


You will need to choose a variety of rocks to make into an artificial reef wall (for fish-only tanks) or a base for live rock (in a mini-reef aquarium). Some options include tufa, limestone, coquina, and lava rock. The rockwork should be attached to the bottom of the tank (preferably with aquarium-safe silicone) prior to adding the substrate. If you’re using live rock, however, it should be placed in the tank once the tank has been partially filled with water.


In their natural reef environment, marine fish will experience amazingly stable water parameters, including water temperature. The ideal temperature range for most marine fish found in coral reefs is between 72° and 79°F. In a home aquarium, a temperature somewhere within that range should be established and kept as consistent as possible. The easiest way to accomplish this task is to purchase a heater.

Aquarium heaters are fairly inexpensive and will do the job quite well. Submersible heaters contain a heating element and a thermostat in a small glass tube that can be attached to the wall of the tank with suction cups or hidden among the rockwork in the tank. There are also heaters available that clamp to the top of the aquarium, putting a glass tube into the aquarium and leaving the temperature adjustment dial above the surface. No matter which kind of heater you choose, make sure the temperature settings are easy to read, it can be easily adjusted while still in the aquarium, and it is fairly sturdy and not easily damaged.

When purchasing a heater for your aquarium, you will need to decide how much wattage it will have. Simply put, the higher the wattage of a heater, the faster it will be able to raise the temperature of the aquarium water. You will want the heater to have approximately 5 watts for every gallon of water in your tank (or 3 watts per gallon for a large tank). For example, a 75-gallon tank will require a heater of 250 watts. This wattage can come from one heater or a combination of two heaters.


The lighting you choose for your saltwater tank will depend on whether your tank will contain only fish or be a mini-reef tank. Fish-only tanks require no special lighting other than that which will allow for the most optimal viewing of these beautiful creatures. A standard pair of normal output fluorescent lamps should do the trick, with the amount of wattage to be determined by the size of the tank.

Lighting plays a very important and complex role in a mini-reef aquarium. Many marine organisms generally included in such a setup would not survive without lighting of the proper intensity and spectrum, so you will need to provide artificial lighting that imitates natural lighting as closely as possible. As with heating, you will want your lighting system to produce a minimum of 3 to 5 watts per gallon of water.

Fluorescent fixtures and metal halide lamps are light sources commonly used in mini-reef aquariums. Fluorescent lighting is usually more convenient, less expensive to purchase and to operate, and outputs less heat while running. On the other hand, fluorescent tubes can really only be used in shallow tanks (20 inches high or less) because they don’t penetrate the water very deeply.

Metal halides produce an intense light that penetrates much deeper than the lighting produced by fluorescent tubes. However, metal halides get exceptionally hot, which means a tank with this source of lighting will also require a cooling fan to maintain the correct water temperature. Metal halides are also more expensive than fluorescents to purchase and to operate.

For most fish-only aquariums, six to eight hours of light a day is ample. This amount of lighting will give the fish a predictable night and day cycle and allow them to feed by light. Keeping the amount of hours to a minimum will help to save on your energy costs and keep the algae in the tank at bay.

A mini-reef aquarium should be lit for about 10 to 12 hours every day. This schedule can be tweaked according to the way the organisms in the tank respond. Some may require slightly more or less light.


In the ocean, any waste products that a fish produces are quickly scavenged or diluted. In a home aquarium, these waste products can easily build up with disastrous results for your tank. The solution to this potential problem is adding a filter to your tank setup. There are three forms of filtration: mechanical, chemical, and biological. Mechanical filtration is probably the easiest method to understand. A mechanical filter simply strains out and removes waste from the tank, giving your tank more aesthetic appeal and keeping the water clean. Mechanical filtration can be achieved with a hang-on-tank filter or a canister filter.

Chemical filtration refers to the use of activated carbon to remove dissolved organic compounds from tank water. When activated carbon is placed in a tank’s filtration system, water will flow through the tiny pores in the carbon and dissolved compounds will be adsorbed (not absorbed) from the water, meaning they will form a chemical bond with the carbon, effectively removing them from the system. Chemical filtration can be accomplished by a hang-on-tank or canister filter in addition to mechanical filtration.

Biological filtration is also referred to as "nitrification." Ammonia, which is toxic to both fish and invertebrates, is constantly released into the aquarium water through fish waste or other debris. The bacteria that feed on ammonia quickly begin converting it into nitrite, which is less toxic than ammonia but still very harmful to fish and invertebrates. Next, bacteria that feed on nitrite begin breaking it down into the final product, which is nitrate. Nitrate is toxic to some invertebrates but moderately tolerated by fish.

To remove nitrate from your aquarium (especially important for a mini-reef aquarium), you have several options. First of all, you can purchase a nitrate-removing filter media to try to chemically filter it from the water, but this method does not provide consistent results. You can also attempt to remove it naturally, but the most reliable way to eliminate nitrate is to perform a water change.

In summary, nitrification (biological filtration) is a natural process, but in order to keep it running smoothly, you will need to make sure you provide the special nitrifying bacteria that perform biological filtration (and naturally occur in all tanks) with the food, oxygen, and surface area they need to survive. Without biological filtration, you tank is a disaster waiting to happen.

For more detailed information on mechanical, chemical, and biological filtration, read The Simple Guide to Marine Aquariums (T.F.H. Publications, Inc.).