In the early days of marine aquarium maintenance, enthusiasts collected saltwater at the beach. This practice introduced parasites and pollutants to tanks, and often killed expensive marine organisms. Today, marine aquariums contain chemically-defined saltwater, which is tested for safety and salinity levels before being introduced to the tank.

The Marine Aquarium

A marine aquarium tank is usually made of glass or acrylic. It can be placed on a stand or built into a wall. It will also contain equipment for chemical, biological, and mechanical filtration, along with lighting and heating equipment. All these pieces of equipment are essential in keeping the environment of the marine aquarium as close to that of seawater as possible.

There are different kinds of marine aquarium fish keeping methods. The FO, or fish only tanks will contain only marine fish, along with some pebbles to coat the aquarium floor. In the fish only with live rock system, or FOWLR, fish are kept along with microorganisms that are present in live rocks, such as essential algae, invertebrates, and bacteria. The reef tank will contain sea anemones, delicate marine invertebrates, and corals, and will have a carefully controlled lighting system.

The Marine Aquariums Filtration System

Because marine aquarium tanks will often accumulate large amounts of microorganisms, and because the carefully controlled pH levels of the water can also be inviting to microorganisms that can damage marine organisms, a filtration system is necessary to maintain a marine aquarium. There are various methods of filtration suitable to maintain the integrity of a marine tank, and all these methods will combine chemical, biological, and mechanical filtration.

Simple hang on filters can contain plates where beneficial bacteria can form their colonies. These bacteria provide biological filtration, and they shouldn't be cleaned out or expunged, as they provide a healthy biological balance in the marine tank. Larger marine aquarium tanks will also contain bio-filtration media; sometimes, large amounts of live rock can provide their own biological filtration, although molds and fungi can often damage live rock. As a result, marine aquarium enthusiasts and merchants recommend protein skimmers, which can introduce bubbles into the marine aquarium tank. These bubbles mimic the action of wave foam, and will contain waste products, saltwater, plankton, and essential nutrients.

Marine Aquariums Lighting and Heating

Although lighting may seem to be more vanity than a necessity, many marine systems actually need a cycle that balances light and dark hours. This simulation of day and night is essential to maintain the Circadian rhythm of the fish in the tank, an inner biological clock that determines periods of sleep and waking. This biological clock also governs other aspects of fish health. Strong lighting, moreover, can encourage the proliferation of coralline algae, which is important in fish with live rock tanks.

Many marine fish are caught in tropical regions, where the water is warmer than it is in temperate regions. These fish have to be established in a tank that mimics the native temperature of their saltwater, so most marine aquarium tanks also need to be heated. Although some cold water marine fish are also available, they are generally not as colorful or attractive as warm water marine fish.

Saltwater and the Best Marine Environment

Saltwater should be tested before it is introduced to a marine aquarium. Specific gravity is important, as it determines the ion balance in the water. In general, a specific gravity of about 1.020 to 1.024 can be suitable for a fish only tank. A specific gravity of 1.023 to 1.026 is good for supporting the growth of corals and invertebrates. Salinity is also an issue: salt should be at a level of about thirty parts per thousand, and can be measured with a refractometer.

The pH or acidity of the tank should be at about 8.1 to 8.3, which is more alkaline than ordinary water. This can be maintained through the use of buffers, a calcium-rich substratum, or commercially available chemical mixtures. Saltwater also needs to be buffered, and monitored for levels of ammonia, which is toxic, and which is converted to nitrate. Marine animals excrete ammonia into the water through their wastes or gills; bacteria pick this up and convert it into nitrate; the algae and corals use this nitrate to function. Although this balance is ideal, it is difficult to maintain, as nitrates may accumulate faster than algae and corals can take them up. Nitrates are toxic to fish, and can be removed only by changing the water. If you are interested in maintaining a marine aquarium, then make sure that you have all the knowledge necessary to have one. A marine aquarium can be a challenge to build, difficult to maintain, but an enjoyable sight to observe.