67 guide Saltwater aquariums
Successful setup Natural care
Contents The sea: An incredible living world ......... 3 Which marine animals are suitable and which are not? .................................... 4 Preparing your natural biotope .............. 7 Aquarium setup: The substrate .............................................. 8 Biofilter components ................................ 9
Healthy treats & specialties ...................... 17 Regular maintenance: Checking the water ................................... 18 The interaction of pH, CO2 and carbonate hardness ................................... 22
Technical equipment ................................. 11
From ammonium to nitrate: The nitrogen cycle ..................................... 24
Saltwater ...................................................... 12
The calcium level ........................................ 26
The landscape ............................................. 13
Strontium and trace elements ................ 27
The new environment needs time to grow ................................... 14
What to do if a marine animal gets sick? ........................................ 28
Introducing and acclimatizing the marine animals .................................... 15
What you always wanted to know about saltwater .......................... 31
Biofiltration ................................................. 10
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Every animal has its own nutritional requirements .......................... 16
The sea: An incredible living world Almost two thirds of the earth’s surface is covered with water – the vast majority of it open ocean. Yet with all this area, the highest concentrations of fish species exist close to the coral reefs and atolls. Many of the species living in shallow regions can make a comfortable home in saltwater aquariums, as they prefer moderate or warm tropical water and little space. A reef aquarium itself is a small ecosystem influenced by many factors. Over the years, aquarists have had more and more success in keeping soft corals for long healthy lives and finding success at breeding marine fish, which had proven difficult for many years. Before setting up your own saltwater aquarium, take a few minutes to look through this guide. In it you’ll discover the first, but most important, steps to setting up a stunning, healthy saltwater aquarium. This guide is not meant to replace the necessary technical literature that explains and guides you through the exact care for specific organisms – but instead it will help you identify the basics, so that you can do further research on your own. Enjoy the experience!
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Which marine animals are suitable and which are not? First, let’s look at the inhabitants of a saltwater aquarium. If corals, shrimps, and other invertebrates are to be kept in the same aquarium, your choice of compatible fish is reduced. Many fish are predators, and will eat smaller fish, shrimps, or coral tentacles. Even peaceful fish can cause problems:
Seahorses, for example, must be fed frequently, which can lead to water pollution, and they are notoriously slow eaters – so their food is often eaten by other fish. Anthias species are very beautiful but also very demanding fish.
Easy-to-keep fish for first-time marine aquarists These fish can be kept in the same aquarium as invertebrates:
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Damselfish (Chromis, Dascyllus, Chrysiptera)
Gobies (Cryptocentrus, Valencienna)
Cardinal fish (Sphaeramia, former Apogon)
Clownfish (Amphiprion)
Wrasses (Macropharyngodon)
Surgeonfish/Tangs (Acanthurus, Zebrasoma)
Which marine animals are suitable and which are not? Corals Some corals live in a symbiotic relationship with unicellular algae called zooxanthellae. These organisms live in the coral’s tissue, providing them with all nutrients they require – without being fed by humans!
Africana (soft corals), and Tubastrea sp. – at least during the early stages of your marine aquarium experience. With well-maintained water, these invertebrates make hardy aquarium inhabitants:
Other coral species do not feed via zooxanthellae, and must be fed, which leads to heavily polluted water conditions. sera recommends avoiding these species – such as Pennatulacea sp. (sea feather), Lemnalia
Leather corals (Sarcophyton, Lobophyton, Sinularia)
Mushroom anemones (Discosoma)
Anemones (e.g., symbiotic anemones for clownfish)
Colonial anemones (Protopalythoa, Zoanthus)
With some experience also stony corals (Acropora, Porites, etc.)
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Which marine animals are suitable and which are not? Shrimps While many shrimp species are easy to keep, one of the most colorful and fascinating shrimps is the Hippolysmata grabhami, known as the “White banded cleaner shrimp”. This shrimp not only cleans-up food leftovers but cleans the ectoparasites from your fish as well!
Sea urchins Although most sea urchins live on a variety of sea grasses many feed on decaying organic matter or algae – making them wonderful housekeepers for your marine aquarium.
Sea cucumbers Known for their cucumber-shaped body, these animals eat plankton and decaying matter that is suspended in the water or buried in the sand. Consult your retailer before buying a sea cucumber, though, some species can release sticky or toxic substances into the water.
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Preparing your natural biotope Aquarium size Keep this rule in mind when choosing an aquarium: The larger the aquarium, the easier it is to maintain. Larger volumes of water are less easily disrupted by a small fluctuation to water parameters than smaller volumes because the change has more area in which to dissipate – the parameters remain fairly constant. The same fluctuation to a smaller volume of water could provide a severe jolt to the whole biological condition. Aside from water parameter considerations when buying an aquarium, you also need to consider the fish. Most marine fish require substantial territories to defend. For these reasons, sera recommends a 200-liter (53 gal.) tank, or a 100-liter (26 gal.) at the minimum.
For a double-hood aquarium using fluorescent tubes only, sera recommends combining light spectrums for optimal conditions. Consider the sera deep sea special as a foreground tube; it provides actinic blue marine light and, with a specific light spectrum of 380 – 450 nm, it ensures tropical reef light conditions. Growth and coloration of invertebrates are strongly enhanced by the blue light spectrum. We recommend the sera blue sky Royal for supplying the saltwater tank with tropical daylight.
If a bio filter system, a trickle filter for example, is to be installed under the aquarium, ensure that a sufficiently large overflow hole is drilled as a water outlet.
Always combine a metal halide lamp with a blue light tube – the sera deep sea special for example – in aquariums stocked with invertebrates that require plenty of light, or if the aquarium is deeper than 50 cm (20 in.). This ensures the best possible display of your corals’ magnificent color.
Optimal lighting
Support and location
Fluorescent tubes, metal halide lamp (HQI) or their successors HCI or CDM, or a combination of both, are used for lighting saltwater aquariums.
Place the aquarium on a Styrofoam or foam pad (sera thermo-safe) to prevent the glass from cracking. Install the aquarium away from direct sunlight to reduce the risk of algae growth.
If fluorescent tubes are used, the water depth must not exceed 50 cm (20 in.). You can use the sera Combi-Reflectors to increase light intensity by up to 100%.
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Aquarium setup: The substrate The most important task of the substrate is to provide additional settling space for bacteria with a high oxygen demand (aerobic) in the upper layers, and for bacteria that live without oxygen (anaerobic) in the lower layers. Coarse coral sand is the ideal choice for a saltwater aquarium. It is visually attractive, and because of its high lime content it helps stabilize the pH value. Some fish species, such as wrasses and gobies, need a sandy area to dig themselves into for the night. A separate area with coral or quartz sand should be provided for these animals. Consult your retailer for details on the proper depth for your specific fish species. The remaining surface should be covered with a coarse coral sand layer of about 3 cm (1 in.). sera recommends using a rock border between the different substrates to prevent them from mixing.
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Aquarium setup: Biofilter components The saltwater is purified in several steps within the sera internal biofilters B 200 and B 400.
sera filter wool sera biofibres sera biopur
sera super carbon
sera biofibres
e.g. sera siporax®
1. Prefiltration (Mechanical water purification) sera filter wool and sera biofibres catch the large, solid dirt particles – such as uneaten food or clumped dead algae – from entering your primary filter. This prefilter media must be cleaned regularly to maintain the maximum water flow rate, and to prevent additional pollution from the decaying particles. The prefilter’s primary focus is to give the biofilter the best chance at breeding bacterial colonies, undisturbed.
2. Main filtration (Biological water purification) Your biological filter is home to the useful bacteria that biologically break down the pollutants in your aquarium. sera biopur and sera siporax provide the ideal settling conditions for this bacterial colony. One liter (10 oz.) of sera siporax has the same biological breakdown capacity as 34 liters (approx. a 9 gal. pail) of ceramic material. To collect any stray large dirt particles, separate the sera biopur and sera siporax with an additional layer of sera biofibres. We also recommend adding a regular dose of sera ammovec, nitrifying bacteria for saltwater aquariums, to your biofilter. Clean this filter as seldom as possible to avoid destroying the bacterial colonies, which already struggle to multiply in saltwater conditions.
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Aquarium setup: Biofiltration Biological breakdown of pollutants within the filtering cycle
Millions of useful sera ammovec nitrifying bacteria settle within sera siporax to clean the aquarium water. The large open-pored tunnel structure of sera siporax provides a natural living space for these microorganisms, which convert clumps of dead algae, uneaten food, and fish waste into ammonium. Each sera siporax ring is composed of a highly porous material that ensures that a thick layer of outer bacteria develops and is supplied with nutrients and water for growth. As the inner pores fill-in, a low-oxygen thriving bacteria inhabits the ring centers. These break-down nitrate and release beneficial nitrogen into the water.
sera ammovec nitrifying filter bacteria convert clumps of dead algae, uneaten food, and fish waste into ammonium.
Ammonia and ammonium are then converted to nitrite by a second type of filter bacteria.
Yet a third form of bacteria converts the nitrite into nitrate. As nitrate promotes the growth of algae and is especially harmful for invertebrates, a slow flux filter with sera siporax provides a dedicated solution by biologically breaking-down the nitrate. Skimmers reduce pollution in saltwater caused by protein and other organic substances. They must be cleaned regularly to prevent skimmed-off waste from re-entering the aquarium.
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Aquarium setup: Technical equipment Filter
Thermostat control heaters
The sera internal biofilter B was developed according to the requirements for optimal filtration. It is easily accessible from the top, so the prefilter media can be changed without disturbing the biologically active primary filter media. With its practical three chamber design (see pg. 9), this filter lets you exchange a variety of filter media, such as active carbon, as necessary, without dismantling the entire filter. The integrated surface skimmer of the sera internal biofilter B reliably removes organic waste and unwanted surface protein film. You can achieve increased filtering performance from internal filters that use a sponge cartridge by using sera siporax in the primary filter chamber, and sera biofibres or sera biopur in the prefilter.
The sera aquarium heaters should be placed in the clear water chamber of the sera internal biofilter B to prevent wandering invertebrates, such as anemones or snails, from being caught and injured.
The sera internal filters L 60, L 150, and L 300 are ideal for quarantine, breeding, and live food aquariums up to 300 liters. In addition to water filtration, they also oxygenate the water, and the fine-pored external sponge prevents small animals, such as sea cucumbers, from being trapped in the filter.
300 watts 250 watts 200 watts 150 watts 100 watts 75 watts 50 watts 35 cm/ 35 cm/ 30 cm/ 30 cm/ 22 cm/ 22 cm/ 18.5 cm/ 13.8 in. 13.8 in. 11.8 in. 11.8 in. 8.7 in. 8.7 in. 7.3 in.
25 watts 18.5 cm/ 7.3 in.
Pumps Powerheads are the heart of a saltwater aquarium. They provide the animals with natural water movement and changing currents such as high and low tide, which can easily be imitated by timers. Correct placement is critical to ensure there are no “dead spots” in which food and decaying matter can accumulate. To achieve the constant motion, use several sera submersible pumps to keep the water moving in front and behind the live rock. With sera submersible pumps, the water intake pipe can be protected by a sponge. Thus, small animals are prevented from being trapped inside the pump.
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Aquarium setup: Saltwater Sea salt: The crucial starting point
Adjusting for exact salinity
As the use of natural saltwater is not practical, aquarium saltwater must be prepared from purified (reverse osmosis) water and sea salt. Saltwater organisms in aquariums require stable, constant salt conditions. sera sea salt dissolves rapidly and homogenously throughout your aquarium to form crystal clear saltwater. The natural pH and KH balance forms a buffer that maintains a precise and correct pH range. sera sea salt is free from nitrate, silicate, and phosphate, and its prepared saltwater has the biologically correct calcium and magnesium levels.
There are two methods:
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When the free floating sera hydrometer is used for testing, it displays the density of the water on an integrated scale. For example, in aquariums with invertebrates, the density should be between 1.022 and 1.024 g/cm3 at a water temperature of 25°C (77°F). If the temperature of the aquarium water differs from this value, then the estimated density would need to be converted in accordance with an appropriate table, such as the one below. Density Salinity 33 ‰ at
16°C 20°C 25°C 28°C 30°C
Preparing the aquarium water Fill the empty aquarium with purified (reverse osmosis) water and add the prescribed amount of sea salt. sera sea salt dissolves with no residue. When the last salt grains disappear, condition the water with sera aqumarin. Use powerheads, placed on the aquarium floor, to agitate the water for 24 hours. Use a thermostatically controlled heater to warm the water to the desired temperature.
Salinity 34.5 ‰
Salinity 36 ‰
1.025 g/cm3 1.026 g/cm3 1.0265 g/cm3 1.0235 g/cm3 1.025 g/cm3 1.0255 g/cm3 1.022 g/cm3 1.023 g/cm3 1.024 g/cm3 1.0215 g/cm3 1.0225 g/cm3 1.023 g/cm3 1.020 g/cm3 1.0215 g/cm3 1.0225 g/cm3
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The salt concentration of brackish water or saltwater as well as the total pollution degree of freshwater are determined via the conductivity. The sera conductivity meter can be easily switched from the µS/cm (freshwater) to the mS/cm (saltwater) range and thus has a broad application range. It is ideal for owners with many aquariums, for breeders, and for the specialty trade. Further applications are, for example, quality control of R/O (reverse osmosis) water, and monitoring the water for salt that might be released by the decorations or active carbon. Salt concentration too high: Dilute with purified water. Salt concentration too low: Raise by carefully adding sea salt.
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Aquarium setup: The landscape There are no limits to your underwater landscape design when you use your imagination. Ensuring the construction is stable, though, is important. Aquarists often use all-plastic cable fasteners and silicon to secure the decorations. Place an acrylic panel at the bottom of the aquarium to protect the glass against damage from the constructions. The aquarium should preferably be decorated with “live rock.” Why it is called “live” will be obvious after several days. Along with the live rock, dolomite, sand stone, granite, lava rock, and tufa are other choices. Fish, crabs, and other animals in the saltwater aquarium need stones for hiding. Shelters, caves, and ledges are simple to build with reef rocks.
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The new environment needs time to grow
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Development of useful bacteria
Watch your aquarium come to life!
After you have decorated your aquatic world, it needs some time to colonize several strains of bacteria, which will break down pollutants and inhibit the rise of dangerous ammonia and nitrite levels (see page 10). Bacteria multiply slowly in saltwater environments, so we recommend giving your aquarium a head start by adding sera ammovec nitrifying bacteria.
Many small animals and almost certainly a variety of beautiful algae species will have entered the aquarium with the “live rock,” and will become visible as days go by.
During this start-up phase, ammonium and nitrite levels should be monitored frequently with the sera ammonium/ammonia-Test and sera nitrite-Test. When values are in a safe zone, invertebrates and fish can be introduced over the course of time. Check with your specialty retailer for advice.
Lighting
If any of these animals, such as sponges, do not survive, they must be removed immediately to prevent pollution as a result of decay. In any case, another dose of sera ammovec should be added.
For the first week, refrain from turning on the aquarium lighting to prevent detrimental algae growth. Begin lighting the second week, increasing the time by an hour or two a day. The live rock begins developing, and every day there are new organisms to discover. You will see anemones, ornamental algae, crustaceans, and other animals populate your miniature reef.
Introducing and acclimatizing the marine animals Some marine animals must never leave the water. During transport, even a few seconds of exposure to air can be lethal. Among these air-sensitive animals are sea urchins, sea cucumbers, starfish, and pufferfish.
When the new inhabitants are acclimatized to the aquarium water, carefully transfer them to the aquarium. A large glass container is ideal for moving them. Remember that they must never come in contact with air! sera aqumarin supports the fish’s healing processes of the mucous membrane if it has been damaged during transport. Always purchase bred animals when possible – and only those that are suitable for your aquarium!
When purchasing these animals, ensure they are placed in the transport bag under water, and ask your retailer for specific instructions on introducing them into your aquarium. Generally, the transport bags with the newly purchased fish and invertebrates should be opened and securely placed side-by-side in a bucket, and for the following half-hour, drip aquarium water into the transport bags. An air hose fitted with a suction cup and clamp is ideal for this job. By doing this, the animals can adapt to the new water temperature as well as the new water parameters. Place the bucket in a darkened area to reduce stress and help calm the animals.
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Every animal has its own nutritional requirements
Staple diets Compared to freshwater fish, marine fish require much more iodine and other minerals. More than fifty different ingredients in sera fish foods ensure a well balanced diet for the aquarium inhabitants. This helps support the immune system and prevents deficiencies. All sera foods are especially low in phosphate.
sera GVG-mix marin is a flake food with added tidbits for marine fish. This versatile basic food contains iodine and other minerals from marine algae, krill, plankton, and other valuable ingredients such as bloodworms, daphnia, and artemia shrimps.
sera marinvit plus for ornamental algae, stony corals and other invertebrates. This nutrient complex contains strontium and trace elements in biologically correct amounts.
sera coraliquid, a planktonbased, energy-rich liquid food, was specially developed for filtrating invertebrates.
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sera granumarin is an ideal food for fish that search for their food between coral branches, in the middle of the water, or near the bottom. It sinks slowly, softens quickly but nevertheless keeps its solid consistency. Therefore, water pollution is largely avoided.
Healthy treats & specialties
sera flora provides herbivores (plant eaters) with essential vegetable proteins, minerals and roughage.
sera O-nip tablets consist of 50% freeze-dried food animals and 50% high quality flake food, making it an ideal diet for all animals. sera O-nip tablets can be attached to the aquarium glass, and will bring even shy animals into view.
sera Spirulina Tabs can also be attached to the aquarium glass. This all-vegetable tablet contains an optimal 20% of spirulina algae for proper nutrition. sera Spirulina Tabs are indispensable for algaeeating animals such as surgeonfish/ tangs or blennies.
sera FD Shrimp, made of tender brine shrimp is a tasty treat for all saltwater fish.
sera microgran for young fish and small mouthed species is a nutritious blend of ingredients plus added multi-vitamin complex, making sera microgran a perfect staple diet for these fish.
sera micron is best suited for raising fish fry or shrimp larvae. Invertebrates and fish that need powdered food can also be fed sera micron.
sera Plankton Tabs contain an especially high amount of freeze-dried plankton. Fish are fed by simply dropping the tablets into the aquarium. Invertebrates are fed individually, for example, with a pair of tweezers or a plastic tube.
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Regular maintenance: Checking the water ⇓ ⇑
Parameter When to check?
Ideal parameter
Value too high – lower Value too low – raise
pH
8.0 – 8.5
⇓ • Partial water change with more acidic water • Add CO2
Weekly
⇑ • sera pH-plus KH Carbonate hardness
8 – 12°dKH
⇑ • sera kH-plus
Weekly
Ca Calcium
400 – 450 mg/l (ppm)
⇓ • Partial water change ⇑ • Add sera calcium plus
Weekly
Conductivity
⇓ • Partial water change
50 – 54 mS/cm
Weekly
⇓ • Partial water change with water of a little less conductivity ⇑ • Add sera sea salt in small portions until the correct value is achieved
Density
1.022 – 1.024 g/cm3 at 25°C (77°F)
⇓ • Partial water change
Weekly
⇑ • Add sera sea salt in small portions until the correct value is achieved NH4/NH3 Ammonium/ Ammonia
Ideal: 0.0 mg/l (ppm)
Weekly
Depending on the pH value
NO2 Nitrite
Ideal: 0.0 mg/l (ppm)
Weekly
Dangerous from 0.02 mg/l (ppm)
0.3 – 0.9 mg/l (ppm) NO2 (equals 0.1 – 0.3 mg/l [ppm] NO2-N): water pollution From 0.9 mg/l (ppm) NO2 (equals 0.3 mg/l [ppm] NO2-N): danger to fish 3.3 mg/l (ppm) NO2 (equals 1 mg/l [ppm] NO2-N): acute danger to fish
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⇓ • Partial water change (check pH value) • Avoid still water zones by providing water currents (use a water pump) • Add sera ammovec • Check/clean the filter • Reduce number of fish • Feed sparingly ⇓ • Add sera ammovec • Check the filter • Feed sparingly • Check whether a fish or another animal is missing • Partial water change • Remove cause ⇓ • Partial water change • Repeat partial water change after 12 – 24 hours
Regular maintenance: Checking the water ⇓ ⇑
Parameter When to check?
Ideal parameter
Value too high – lower Value too low – raise
NO3 Nitrate
Ideal: maximum 20 mg/l (ppm) From 20 mg/l (ppm)
⇓ • Install a slow flux filter and use sera siporax
Weekly
• Use 1 liter (10 oz.) sera siporax per each 100 liters (26 gal.) of water in the biofilter, and activate with sera ammovec • Carry out frequent partial water changes with water that is low in nitrate • Reduce number of fish if applicable • Feed sparingly • Use a protein skimmer
Mg Magnesium
Above 100 mg/l (ppm)
• Partial water change
About 1300 mg/l (ppm)
⇓ • Partial water change ⇑ • Add sera magnesium plus
Weekly
PO4 Phosphate
Max. 0.1 mg/l (ppm) Ideal: below 0.05 mg/l (ppm)
Weekly
⇓ • Partial water change • Add macro ornamental algae • Feed sparingly • Reduce number of fish
Cu Copper Fresh water Fish feeling unwell
O2 Oxygen
Ideal: 0.0 mg/l (ppm) (any detectable amount severely harms invertebrates or can be fatal to them) Above 1.0 mg/l (ppm): fatal for all living beings in saltwater aquariums
Above 6 mg/l (ppm): sufficient oxygen
⇓ • Add sera aqumarin • Generous partial water changes with copper-free water, prepare fresh water with a double dose sera aqumarin
⇑ • Rapid increase with sera oxypur • Aerate water
Every 2 weeks
Cl Chlorine Water change New setup
Below 0.02 mg/l (ppm)
• Find out and remove cause ⇓ • sera aqumarin neutralizes the effects of chlorine • Add sera chlorvec • Add sera ammovec • Aerate water well
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Regular maintenance As well as monitoring the water parameters and cleaning the filter, several further maintenance measures must be carried out on a regular basis.
Water change
Removal of unwanted algae If large macro ornamental algae, such as Caulerpa, grow in your aquarium, you should carefully control their growth. The rapidly growing Caulerpa algae can actually overgrow the invertebrates. Select and remove the unwanted algae without taking too many at one time. Algae leaves are called “thalli.” They consist of a single cell that releases its nitrate-containing cell liquid into the aquarium if it is not removed properly. The safest way to cutback your algae is to do this:
Change 5 – 10% of the water monthly, preparing the salt mixture in a bucket according to the directions on page 12. This is also an opportune time to use the sera gravel washer to clean the aquarium gravel of debris and detrimental micro-organisms – as we will see in the following sections.
Waste removal To avoid polluting the water, remove any waste, such as dead algae parts, with the sera gravel cleaner or a tweezers, instantly, before it accumulates. Do not wait for scheduled water changes. Look for the rhizome; this is the cord from which the single thalli grow. On it, you will see the fragile spots beside the thalli at which the algae can be broken apart. Snipoff the unwanted segment of the Caulerpa algae, and immediately remove it from the aquarium. Be careful not to damage the algae as this will lead to cell liquid running into the aquarium uncontrollably.
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Regular maintenance R/O water for cleaning and addition
While you are on a holiday
In areas with high levels of nitrate and/or phosphate in the tap water we strongly recommend purchasing an ion exchange or reverse osmosis (R/O) unit. By purifying the water this way, approximately 95% of the dissolved pollutants are removed. R/O water is much more suitable than tap water for water changes and for replacing evaporated water. Tap water must be conditioned by using sera aqumarin according to the instructions. Open aquariums that are lighted with hanging metal halide lights can lose several liters of water through evaporation, every day. This water must be replaced regularly, daily if possible, with R/O water to prevent an increase in salinity.
For short-term vacations (up to 10 days), the animals in your reef aquarium need not be fed. Live rock provides the aquarium with plenty of micro-fauna to serve as a food supply.
Lighting check Fluorescent light tubes lose about 50% of their light-emitting power after six months use, whereas metal halide (HQI) lights have a maximum “lifespan” of two years. As the human eye does not detect the gradual reduction of light, use the exposure lightmeter of a camera as an easy method of monitoring this problem. Note: These tests must be carried out from the same distance and angle each time.
During longer vacations, we recommend setting-up a maintenance plan to give to the person caring for your aquarium while you’re away. Along with feeding instructions, this should include information on topping-up the tank with R/O water, and providing trace elements (sera marinvit plus) for the invertebrates. Advise them on the exact number of food tablets (sera O-nip, sera viformo, sera Spirulina Tabs, sera Plankton Tabs), as well as which days to do the feeding. Tablets are the preferable choice to leave, as inexperienced aquarists usually drastically overfeed with flake and granulated foods, causing severe water pollution.
Camera with exposure meter
Fix distance and angle exactly All settings and conditions must be the same for each test
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The interaction of The ocean represents the most stable ecological system on earth. Over millions of years the ocean’s inhabitants have adapted to the water’s constant physical and chemical changes, but as these parameters vary only slightly in nature, the animals are much less able to adapt than their freshwater counterparts. Because of this – marine aquariums must provide continuously stable conditions. The pH value describes whether the water is acidic (pH below 7), neutral (pH = 7) or alkaline (pH above 7). The pH value in natural saltwater is slightly alkaline (pH 8 to 8.5).
Check the carbonate hardness of the water quickly and accurately with the sera kH-Test.
Increasing the KH level is easy and safe with sera kH-plus.
The pH value of the aquarium water should also be checked regularly with the sera pHTest. In the aquarium the pH is lower in the morning than in the evening. This is because algae consume carbon dioxide (CO2) during the day, resulting in a rise in pH. As a result of the consumption of carbonic acid, the pH value rises during the day.
The carbonate hardness (KH) in the water serves as a buffer. It is able to neutralize acids and therefore absorbs fluctuations of the pH value to a certain degree. To provide a buffering effect that is strong enough for a saltwater aquarium, the carbonate hardness must not fall below 8°dKH.
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Consider using the sera pH meter for precise monitoring of the pH value. You can raise the pH value with sera pH-plus if necessary.
pH, carbon dioxide (CO2), and carbonate hardness (KH)
When aquariums are over-planted with macro ornamental algae (Caulerpa, Halimeda etc.) pH values can rise over 8.5 because of the high CO2 demand. The easiest and most natural method of lowering and stabilizing the pH value is by supplying carbon dioxide to the water. Add carbon dioxide according to the specific aquarium requirements, simply and confidently, with the sera CO2 fertilization system and seramic CO2 control system.
The seramic CO2 control system is ideal for the automatic control and regulation of the pH value in your aquarium. Simply set the desired pH value and let the seramic CO2 control system inject the precise amount of carbon dioxide for stable conditions. This highly effective CO2 control unit system also shuts-off automatically when the correct pH value has been reached. Saltwater aquariums demand a considerable amount of the CO2, which should not be underestimated. Even if you do not continuously supply the aquarium with CO2, we strongly urge you to keep CO2 in stock. This way, you can react immediately if the pH value and the ammonia level become too high (see sections “The nitrogen cycle” and “Checking the water”).
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From ammonium to nitrate: Let’s have a closer look at the nitrogen cycle: Organic waste products in the aquarium result in nitrogen pollution of the water. Among those waste products are excretions of the fish, uneaten food, and rotting algae, as well as dead animals. Nitrogen occurs in the aquarium in different forms. Nitrogen containing waste products in the aquarium are excess protein, ammonium and ammonia, nitrite, and nitrate.
The useful bacteria in sera ammovec process dead plant parts, food leftovers, and fish waste from ammonia via nitrite into non-toxic nitrate
Well balanced planting lowers nitrate levels
Nitrate-free water
The waste products mentioned contain proteins, from which ammonium converted to ammonia is formed via biological decomposition. The ratio between relatively harmless ammonium and toxic ammonia is determined by the pH value. The higher the pH value, the more ammonia is formed. Since the pH value in saltwater is always above 7, the ammonium level must be checked frequently.
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Check the total concentration of ammonium and ammonia with the sera ammonium/ammonia-Test. The chart included in the test kit makes it easy to determine the level of free ammonia by comparing the measured value and the pH value. If the concentration of free ammonia is above 0.2 mg/l, a partial water change must be done immediately, and sera ammovec should be added. The next step in the nitrogen cycle is the biological conversion of ammonium into ammonia, and then into nitrite by Nitrosomonas bacteria. For this to happen the bacteria need oxygen. Therefore, this is called an aerobic (with oxygen) process. Nitrite is highly toxic to fish and invertebrates. Increased ammonium, nitrite, or nitrate levels result from mistakes or improper aquarium maintenance. Another cause could be an insufficient surface area for useful bacteria to colonize.
Check the nitrite level of the aquarium water with the sera nitriteTest. If the value exceeds 0.3 mg/l (ppm), a partial water change is necessary.
The nitrogen cycle Lower the ammonium and nitrite levels with sera ammovec. sera ammovec is a biological product containing nitrifying bacteria that breaks down ammonium and nitrite. Simply add the liquid to the aquarium water according to the product’s directions for use.
Nitrate is considerably less toxic than ammonia and nitrite. Nevertheless it harms delicate corals when in concentrations of 20 mg/l (ppm) or higher, and it promotes the growth of unwanted thread and slime algae.
The biological decomposition of nitrite by Nitrobacter bacteria leads to nitrate. Also, at this stage the bacteria need oxygen to thrive. Nitrosomonas and Nitrobacter bacteria live in all the oxygen-rich zones of the aquarium, which include the upper gravel layers, the filter, and the live rock surfaces. From this we see that oxygen-rich water is important not only for the fish and invertebrates, but at the bacterial level as well.
Check the nitrate level in the aquarium with the sera nitrate-Test. Nitrate breakdown can take place only in oxygen-poor zones. There the bacteria take oxygen from the nitrate. This is called an anaerobic (without oxygen) process. This final step produces harmless nitrogen gas that escapes into the atmosphere. The biological breakdown of nitrate is achieved by a slow flux filter with sera siporax.
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The calcium level Calcareous algae, fish, and invertebrates extract calcium from the saltwater to buildup their skeleton. Natural saltwater contains about 400 – 450 mg/l (ppm) calcium. Saltwater that is prepared with sera sea salt begins with the correct calcium concentration, but is nevertheless constantly lowered by regular, necessary consumption.
The calcium level in saltwater can easily and safely be determined by using the sera calcium-Test. If the level falls below 400 mg/l (ppm), the calcium concentration can be increased with sera calcium plus.
Unlike kalkwasser, sera calcium plus affects neither the pH value nor the trace elements.
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Strontium and trace elements The magnesium level in natural saltwater is about 1300 mg/l (ppm). Replenish consumed magnesium according to aquarium requirements with easy-to-dose sera magnesium plus.
Use the sera magnesium-Test to monitor the exact magnesium level.
Saltwater that is freshly prepared with sera sea salt contains all the trace elements that are important for your marine life. Although the level of these trace elements are very low (example: manganese 0.2 µg/l [ppm], gold 0.004 µg/l [ppm]), they are essential for fish and invertebrates. Protein skimmers, along with natural consumption, eventually reduce the level of trace elements. Stony corals and other invertebrates need strontium, besides calcium, to build-up their calcareous skeleton. Due to its comparatively high concentration in saltwater (8 mg/l [ppm]) strontium is not regarded as a trace element. Regular addition of sera marinvit plus ensures the ideal supply of strontium for corals and other invertebrates. It contains all the trace elements, in the biologically correct amounts, that are necessary for keeping and breeding ornamental marine algae and invertebrates.
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What to do if a marine animal gets sick? Invertebrates With a good maintenance routine, invertebrates are rarely affected by disease. Nevertheless, certain aspects should be taken into account: • If the water temperature exceeds 30°C (86°F), the skeleton formation of stony corals is disturbed. Furthermore, the symbiotic algae that live in the tissues of the coral (Zooxanthellae) die and as a result the coral also dies. • Crustaceans regularly shed their skin. The water must contain 400 – 450 mg/l (ppm) calcium for building up a new shell. The carbonate hardness must be between 8 – 10°dKH. • If an invertebrate’s growth becomes stunted, despite the best possible maintenance conditions, the animal should be examined for external parasites. These parasites could be miniscule and possibly come out only at night. Planarians are flat white or red worms of approximately 5 mm (0.2 in.) in size. They can harm anemones, corals and other vertebrates with their excreted slime. These worms can be siphoned-out of the aquarium by means of a flexible tube. Sometimes it is useful to place a strong flashlight above the
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aquarium at night. Many planarians assemble in the light and they are much easier to remove. Watch invertebrates thoroughly before buying them! Small, brownish-red, oval spots are usually planarians. Bristle worms (Polychaetes) are actually carrion eaters, and will eventually nibble on mushroom anemones and stony corals. Furthermore, they tear their prey away from them and, in doing so, often injure these sessile (immobile) animals with their sharp jaws. It is possible to attract Bristle worms with fish meat and then catch and remove them. As they are mainly active at night, this procedure should be carried out in the dark. Be careful: Do not touch these worms. The bristles break off and may cause skin inflammations! Small bristle worms hide in the gravel during daytime and can be removed by siphoning off a larger quantity of the gravel (approx. 30 – 50%) and washing it with fresh water. Usually, this is sufficient to remove these Polychaetes from time to time.
What to do if a marine animal gets sick? Many snails nibble on sea anemones, corals, and other invertebrates. In a reef aquarium every snail should be carefully removed with a pair of tweezers. Some snails feed exclusively on sessile invertebrates.
Fish The best way to combat disease is by avoiding it, and the danger of a disease outbreak is greatly reduced by following regular maintenance routines, and by adding sera fishtamin and sera activant vitamins to your fish’s diet. If disease does occur, sera has a line of support products that are safe and reliable to use.
The most frequent and disturbing diseases that affect marine fish – and the recommended care for your fish while ill, are described below. Predatory shrimp species, for example marbled shrimps (different Saron species), can literally cut up anemones. These animals, which are active at night, should be siphoned off with a flexible tube or removed with a pair of tweezers.
Parasitic diseases caused by micro-organisms such as bacteria, or unicellular parasites, can only occur after preliminary damage has been caused by a chemical, such as ozone, hydrogen peroxide, or phosphate, and they are almost never observed in well maintained aquariums. Combating these parasites with treatments is impossible, as treatments, of course, cannot differentiate between “desirable” and “undesirable” invertebrates.
The parasitic Oodinium ocellatum (Velvet, or Coral Fish disease), in saltwater, attacks the gills before migrating to the skin – often leaving the fish unable to pass sufficient oxygen to breath. Copper-based products, used carefully, such as sera oodinopur have been effective – although copper must never be used in aquariums with invertebrates. Apply only in a quarantine tank.
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What to do if a marine animal gets sick? The ciliate Cryptocarion irritans resembles the freshwater parasite Ichthyophthirius (white spot) and is therefore also called “Saltwater Ich”. Use sera cyprinopur according to the instructions for symptoms of white spots of up to 1 millimeter in diameter and strong scraping movements of the fish. sera cyprinopur is harmful for some invertebrates (e.g., stony corals, snails, shrimp) and for safety purposes should be applied only in a quarantine tank.
As many invertebrates do not tolerate treatments, we recommend caring for your fish in a quarantine aquarium. Illness can considerably weaken a fish. Once treatments are complete, sera fishtamin or sera activant vitamins are ideal to help support the animal’s immune system while healing. Use of treatments in the aquarium cannot distinguish between good and bad bacteria, and attacks them all. After every treatment, use sera ammovec, according to directions, to help regenerate the filter bacteria colonies. Use sera super carbon to remove the treatments residue from the water after treatments.
Bacteria can cause many noticeable symptoms in your fish – among them, are skin slime and fin rot. Use sera baktopur and sera baktopur direct, according to directions, at the first sign of symptoms.
Cleaner wrasses and cleaner shrimps help prevent the problem by “preening” the ectoparasite from your fish. Also some nettling coral species (e.g., gorgonians) have positive effects on fish diseases. The best disease prevention measures are good, constant water conditions, varied nutrition, and an appropriate vitamin supply.
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What you always wanted to know about saltwater What is “kalkwasser?” A saturated solution of calcium hydroxide in water is called kalkwasser. This concentrated alkaline solution raises the calcium level of the water without raising the carbonate hardness – it can, however, elevate the pH to uncontrollably high values. In the past, kalkwasser was the most practicable method of providing calcium but this is now considered risky. sera calcium plus does not affect the pH value and is therefore safer to use, making kalkwasser an unnecessary part of your maintenance routine.
What is a protein skimmer good for? A skimmer helps to reduce the aquarium water pollution. Proteins attach to the air bubbles produced by the skimmer, forming solid foam. This foam is pushed upwards within the foam tube, thus removing the skimmed substances from the aquarium water circuit.
What does a calcium reactor do? Many corals, mussels, and calcareous red algae require dissolved calcium for their growth. Using carbonic acid (dissolved CO2), lime material is dissolved to form soluble calcium compounds within the calcium reactor. As this process takes place below pH values of 6.5 – 7 only, a portion of the added carbonic acid is required to lower the pH value within the reactor. The remaining portion is then used to dissolve lime. The pH control required for this is achieved by the seramic CO2 control system.
What is “live rock?” Live rocks are reef rock pieces that are imported together with herbal and animal periphyton organisms. It must be transported moist and tempered. In pet stores they are kept like corals in aquariums. They will bring many useful small organisms into your aquarium and therefore promote natural conditions. Speak with your specialty retailer for more information on adding live rock to your aquarium.
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