Almost any current aquariums are appropriate for either freshwater or saltwater usage. The aquarium must be completely glass or acrylic for saltwater usage; older steel-framed tanks are not permitted.
We normally propose a minimum capacity of 150 liters, which equates to a conventional 3-foot tank. This capacity will keep the temperature and water quality somewhat steady, and it is big enough to house a respectable number of fish or very huge specimens. However, this does not exclude the use of smaller aquaria for marine tanks. In reality, current all-in-one aquaria with over-tank trickling filters are well suited for marine systems, even as micro-reef tanks as tiny as 25 liters. These are reasonably inexpensive methods to go marine, but keep in mind that the size will limit the quantity and sort of fish you may maintain. Aside from these systems, additional tiny aquaria may be built up marine, but they must be at least 35 liters in size.
Biological filtration is critical in the majority of marine aquariums. This is related not only to the fact that saltwater fish are more sensitive to waste products in the water but also to the fact that ammonia becomes much more hazardous at higher pH levels. Ammonia is significantly more harmful in salt water, which has an alkaline pH of slightly over 8 than in freshwater, where the pH is normally around neutral (ie, 7). A biological filter is one that uses naturally existing bacteria to convert hazardous ammonia from fish wastes to nitrite (which is still highly toxic) and then to nitrate, which is considerably less toxic. We suggest that you read our filtering FAQ for additional details on this procedure.
There are many varieties of biological filters available, including overflow filters, canisters, under gravel filters, and trickling filters. A canister filter is by far the best solution in most circumstances. These are more efficient than overflows and undergravels, are generally inexpensive and simple to utilize, and the media may be modified to meet varied needs, such as fish vs. reef systems. They can hold chemical media like carbon, which is highly important in marine aquarium filtration.
Overflow filters perform well in tiny systems with little load – they are ideal for seahorses, for example. They will, however, struggle on bigger tanks. Undergravels are a low-cost solution, but they have some disadvantages. The gravel bed needs to be cleaned properly on a regular basis, making them high maintenance and unsuitable for reef tanks. Furthermore, and most significantly, illness treatment in a marine aquarium with undergravel filtration is almost difficult.
Trickle filters are often praised as the optimum method for marine tanks, however, they are the most costly and time-consuming alternative. They offer great biological filtration, but they are overkill for many hobbyists’ requirements, and the fact that they oxidize wastes so quickly might also be a disadvantage for reef aquaria. Our experience has shown us that having a very successful marine tank without trickle filtering is quite achievable (and not at all difficult!). A sump without a medium is sometimes utilized. This is excellent for housing the skimmer and other equipment, as well as increasing the amount of water. However, these benefits must be balanced against the drawbacks. When using a trickling filter or sump, the method of transporting water from the tank to the sump must be considered.
It may seem weird, but invertebrates need less biological filtration than fish. Why? For starters, invertebrates generate less trash than fish. Second, they can withstand more ammonia and nitrite than fish, but less nitrate. Biological filtration is still required, however, if you are constructing a reef for a small number of fish, you may want to use more chemical and/or mechanical filter media (see below) in your canister and less biological media than in a fish-only system. Some reef aquariums forego traditional biological filtration entirely, instead relying on the microorganisms that colonize the rock and sand surfaces (often referred to as “live” rock or sand) to provide biological filtration as well as de-nitrification (the breakdown of nitrate) and strong protein skimming. This approach may not work when large numbers of fish are housed, but it has worked well for a variety of corals in professional reef aquariums.
Mechanical filtration will be required in addition to biological filtering to remove suspended particles and solid organic wastes. Canister and overflow filters use a combination of filter materials to offer biological and mechanical filtration. Chemical filtration is the third form of filtering. Chemical media bind to dissolved pollutants and poisons in the water. It is not required to have chemical filtration, but it does assist to enhance water quality and clarity. Carbon is the most often used and recommended chemical filter media because it absorbs a broad spectrum of organic and other contaminants. Many canister filters include carbon, and it is simple to add it to those that do not. Toxins may be re-released into the water if carbon is not changed at least every two months, and it should never be kept in the canister for an extended period of time. It is preferable not to utilize chemical media if you are not willing to change it on a regular basis. Because carbon will eliminate drugs, it should not be utilized while establishing a hospital or quarantine tank. Other chemical media target more particular concerns; for example, some remove ammonia, while others aid in the removal of nitrate or algae-promoting waste products.
Because most marine fish and invertebrates can endure high water flows, it is difficult to over filter a marine tank. Aim for a water turnover rate of at least 5 times per hour. Extra powerheads may be employed in reef systems to provide the strong currents desired by many corals and to promote biological filtration/de-nitrification by living rock organisms.
Protein skimming may enhance the water quality in marine aquariums even further. Protein skimmers are a kind of filter that uses tiny air bubble injections to remove ammonia-producing proteinaceous wastes before they degrade. When fine air bubbles are injected into salt water, proteins are drawn to the bubbles and ejected as foam. (This is the same mechanism that creates the foam that is swept up on beaches by the waves.) The protein skimmer collects this froth, which may subsequently be removed. Protein skimmers are highly recommended, even though they are not strictly necessary, especially for reef systems. Protein removal minimizes the quantity of nitrate generated and hence helps to maintain nitrate levels low.
Heating or cooling
Almost all marine fish sold in supermarkets originate from tropical coral reef regions like Australia’s Great Barrier Reef. The temperature in tropical oceans is relatively steady at roughly 25°C. This temperature is comparable to that needed by freshwater tropical fish, and the same aquarium heater may be used. All excellent heaters are thermostatically regulated and adjustable. We usually suggest having a top-quality heater for marine tanks since they have more precise thermostats for better temperature control.
If you’re going to gather your own marines, you should examine the temperature in the region where you’ll be collecting. What is the highest temperature in the summer and the lowest temperature in the winter? This will give you an idea of the temperature range that the organisms you’re collecting can withstand. Even in the summer, water temperatures in many temperate locations remain below 20°C. In hot weather, it is generally difficult to maintain an aquarium temperature below 28°C, and most invertebrates (as well as many fish) from temperate climates will not withstand this temperature. Chilling systems are available, but they are rather costly, beginning at roughly $1,000. Because certain chillers are not thermostatically regulated, you may need to use both the chiller and the heater (set to a low temperature) to maintain a consistent temperature. This is not to say that temperate species cannot be kept affordably; many are temperature resistant and do not need chilling. If you prefer not to purchase a chiller, you need to exercise more caution when picking species to ensure they can withstand the projected temperature in your aquarium.
A thermometer is required to check the temperature regardless of the method you use. This will first confirm that your heater or chiller is operational. Second, if you don’t have a chiller, the temperature may soar beyond 25°C in the summer. When not in use, the heater will switch off, but it will not chill the water. It’s a good idea to keep an eye on the temperature to make sure it doesn’t become too hot. Most tropical marine fish can survive temperatures ranging from 30 to 32°C as long as the water is sufficiently filtered and oxygenated, while invertebrates may suffer around 28°C. More information about managing temperature in hot weather may be found in the next section.
One of the most important needs of marine aquariums is lighting. This may be highly deceptive. Fish and almost all invertebrates have no specific illumination needs. Only hard corals, algae, and a few specialized invertebrates (such as anemones and clams) need bright illumination. Of course, lighting is essential in a fish-only aquarium to highlight the fish – there’s no sense maintaining gorgeous marine species if you can’t see them! – but it doesn’t have to be a specialized system. In most circumstances, a single fluorescent fitting will be enough for fish. We do advise using high-intensity tubes. These feature a spectrum that better represents the brilliant sunshine of shallow oceans and brings out the colors of marines more than conventional intensity tubes. Use numerous fittings or power compact fluorescent lights in deeper tanks for a particularly dazzling impact.
As previously said, lighting is one of the aspects of reef tanks that need special attention. The amount of light required will vary depending on the organisms being maintained. Some corals and other species, such as clams, depend nearly entirely on light for energy and need very intense illumination. Others need enough illumination, while others dwell beneath overhangs or in caves and do not require any light at all. It is extremely suggested that you have some concept of what corals you wish to preserve before selecting lighting.
Fluorescent, power compact fluorescent, and metal halide lighting are all options.
When using normal fluorescent lighting, it is advisable to utilize numerous fittings and high-intensity tubes. The best spectrum for corals is produced by combining two to three high-intensity white fluorescent tubes with one actinic (blue) tube, although when only two fittings are available, it is preferable to use two bright white tubes rather than one white and one blue. Fluorescent lighting is quite inexpensive to acquire and operate, and it generates very little heat.
In many circumstances, power compact fluorescents have surpassed regular fluorescents. Power compact fluorescents use a different tube than standard fluorescents and generate around twice the light per watt. Power compact units are less expensive to acquire and operate per unit of light intensity than ordinary fluorescents. Compact tubes come in a variety of spectrums, including actinics and split-color tubes. Power compacts give enough light intensity for the majority of coral species. They generate somewhat more heat than normal fluorescents, but not enough to cause heat buildup in most situations.
Metal halide lighting may provide better illumination once again. These are considered the peak of illumination yet are much more costly. Metal halide lighting enables you to light very deep aquaria while keeping even the most demanding corals and invertebrates alive (providing your water quality is also suitable). However, their power consumption and heat production are much higher than those of other lighting techniques.
Consider what you want to preserve in your reef as well as your total budget when selecting lights for it. If you have a restricted budget, don’t scrimp on filtration to obtain better lighting: water quality is the most important factor.
Synthetic sea salt
For a variety of reasons, synthetic sea salt is preferred over real seawater. As previously stated, getting an unpolluted supply of natural seawater is difficult, and even then, the water will include many planktonic creatures that die and release ammonia. Aside from that, synthetic salts enhance the water quality in the seas. They have additional carbonates for pH stability, and extra trace elements for fish health and coral development, and a good salt should not include nitrates or phosphates.
In general, synthetic sea salt should be blended with tap water that has been treated with a high-quality water conditioner. However, if you reside in a home with copper pipes, it is strongly advised to let the water flow for five minutes before using it. The initial water that comes out of the tap may include a high quantity of copper, which is hazardous to invertebrates and certain fish. Alternatively, before using the water, filter it using activated carbon. If you have access to reverse osmosis water, you will have the cleanest synthetic salt combination conceivable. Some serious hobbyists utilise this, although it may be a pricey alternative. In most circumstances, it is not required.
To achieve the appropriate specific gravity of 1.021 – 1.022, 30 to 35 grams of synthetic sea salt are usually required per liter of water, but you should verify the directions on your brand of salt to be sure.
A hydrometer is used to determine specific gravity; for more information, see the testing equipment section.
Substrate & decoration
Aquarium gravels are water inert, therefore they may be used in both freshwater and saltwater aquariums. However, in marine aquaria, it is strongly advised to employ a carbonate-based substrate to assist maintain the pH steady. Marble is the most easily accessible and acceptable alternative. It is available in a variety of grades, with fine being the most desirable. Coral sand is also a suitable substrate, but it cannot be transported into Australia and is thus difficult to get. Furthermore, the gathering of coral rubble/sand may affect sensitive reef ecosystems, therefore prudent marine aquarists should avoid it. Shell grit may also be used, but it must be extremely clean. Grit supplied for birds, for example, is not normally of a quality suited for marine aquaria. Of course, you may combine carbonate-based gravel with other aquarium gravel to get the desired color and effect.
The depth of substrate required is determined by your setup and filtration. A shallow bed is easier to clean and will not harbour whitespot or velvet infections. A deep gravel bed, on the other hand, may support de-nitrifying microorganisms that break down nitrate. A layer of at least 2 to 3cm is suggested for proper support of pebbles and ornaments.
It is sometimes advised not to use gravel at all. This is the cleanest way, although it’s not very appealing for a home aquarium. It also implies you don’t have additional pH stability, and there are two more disadvantages. To begin, with a bare bottom tank, you must be very cautious with decorations (particularly pebbles), since it is very simple to shatter the foundation glass. Second, many fish like digging or burrowing in the gravel and will be unhappy in a tank with no substrate. Third, the tank has less surface area for beneficial microorganisms. Bare bottom tanks are typically utilized in storage and import facilities, as well as in quarantine tanks where fish are housed for a limited period of time. In these circumstances, the bare bottom tank enables the most complete cleaning and disease prevention.
There are several décor possibilities for marine aquariums. First and foremost, any aquarium decorations (for example, ceramic and polyresin ornaments, as well as silk and plastic plants) are appropriate. Sandstone and slate rocks, as well as limestone, which is not appropriate for freshwater, may be utilized. Shells and coral skeletons may also be utilized as long as they are clean and unpainted. Driftwood is not suited since it rots fast in seawater. There are few live plants available, however corals and anemones may be utilized in a reef setup.
The salt level of the water is the first item you should evaluate in your marine aquarium. The most frequent way to accomplish this is using a hydrometer. A hydrometer measures the density or specific gravity of water, but since this is influenced by the salt content, it is a reliable and simple proxy to employ. Specific gravity is affected somewhat by temperature. Aquarium hydrometers are calibrated for usage at 25°C; if you use the hydrometer in cooler water, you will obtain a little higher result than is really true.
There are two kinds of hydrometers available: floating and chamber. Floating hydrometers are put in the water to be tested and float higher or lower depending on the salt concentration (higher for greater salt content/specific gravity). These hydrometers are less expensive, but they are more sensitive and need more time to operate since water must generally be removed from the tank and placed in a separate container for testing. Chamber hydrometers are simply filled with water to be tested, and the specific gravity is shown by a floating arm. These are the most popular since they are strong and simple to use.
In addition to a hydrometer, you will need test kits to determine the quality of your water. When the tank is first installed, it will go through a process known as cycling. To begin with, the good bacteria that break down ammonia and nitrite are absent, and their establishment takes time. During this time, ammonia and nitrite may accumulate to high proportions until the bacteria establish (for more information on the nitrogen cycle, read our Filtration FAQ). The characteristics of cycling in saline water are discussed in further depth in the next section). It is critical to monitor these levels to ensure that they do not exceed acceptable limits and to detect when the cycle is complete. Ammonia and nitrite levels should remain nil once the tank has cycled. Checking them on a regular basis (e.g., weekly) or whenever a problem is suspected is still advised to guarantee this is the case.
Nitrate is the end product of biological filtration. This is less hazardous to fish than ammonia or nitrite, but it is poisonous to invertebrates (especially corals and anemones) at low concentrations. Because nitrate is only properly eliminated by conducting water changes in most setups, testing for nitrate is strongly suggested to confirm that the maintenance you are undertaking is sufficient. However, nitrate testing is not required during the first few weeks since it will be undetected until after cycling is done.
pH testing is also a good idea. A high-range kit is required since pH testing for freshwater only measures a pH of 7, but the pH of salt water should be around 8. As previously said, pH in seawater is normally relatively stable; nevertheless, if a pH reduction is noted, a water change should be conducted as soon as possible, since fish and invertebrates cannot withstand too low a pH. Carbonate hardness contributes to pH stability, hence checking this will assure proper pH stability.
It is also advised to test for calcium in a reef tank since this is a necessary factor for optimum coral development. Phosphate testing is indicated in areas where algal issues arise. While phosphate is not poisonous, it may build in aquaria and cause a variety of algal issues.
Other recommended equipment & treatments
Other elements that are suggested but not always required include an air pump for increased oxygenation, water pumps (powerheads) for increased circulation and aeration, and UV sterilization and/or ozone for disease and algae management. To treat the water, you will also require a chlorine neutralizer (water conditioner).
Most filters do a good job of aerating the water, but marine fish need more oxygen than freshwater fish. Oxygen is also required to facilitate appropriate ammonia and nitrite breakdown. Running an air pump or additional circulation pumps will ensure that the water is sufficiently aerated and will serve as a backup should the primary filter fail. An air pump may also give a pleasing aesthetic effect, however bubbles in salt water are finer than in freshwater and might provide a foggy look to the tank if caught in circulation. Additional water pumps are useful in reef aquariums because corals need turbulent water flow. Water flow also helps microorganisms in the rockwork remove waste.
UV sterilizers employ ultraviolet light to eliminate disease-causing organisms and algal spores in water. Running a UV sterilizer is one of the most effective methods to prevent marine whitespot and velvet, which may be tough to treat otherwise, particularly in a reef tank. They are highly suggested for keeping tangs, box fish, or other whitespot-prone species, and they also assist to prevent algae. They cannot, however, destroy whitespot or velvet parasites that are already on the fish. Ozone also destroys parasites and algae spores in the water. It also improves foaming in protein skimmers and increases water oxygen content. It should not, however, be used directly in the aquarium.
Aside from these items, there are numerous other gadgets and additives that can help you maintain your aquarium. Gravel cleaners are highly recommended since they maintain the gravel bed clear of dirt and avoid the need to ever strip out the tank. Scrapers and magnet cleaners aid in the removal of algae, while surface skimmer attachments for canister and overflow filters aid in the removal of the surface film. There are additives available to increase the trace elements required by fish and corals, increase carbonate hardness, manage algae, cure illnesses, and improve water purity and quality. While certain treatments may be used in both freshwater and saltwater, many freshwater treatments cannot be utilized in saltwater. Furthermore, therapies that are safe for marine fish may be toxic to invertebrates. Before utilizing any chemicals in your tank, you should double-check.