Here some article from 1st chapter of my
NAGA MERAH ,the real AROWANA DIGGEST for experts :
Introduction :
LIGHTING
Anyone who is experienced in this hobby will agree that full-spectrum illumination or, better yet, sunlight will enhance and improve skin condition and color in.
Lighting also provides the fish with certain metabolic capabilities. Without a full-spectrum light source such as natural sunlight or full-spectrum fluorescent bulbs, the fish will not be able to activate Vitamin D in their skin cells and will eventually suffer calcium abnormalities, which may stunt growth or depress the immune system.
Darkness is just as important as lighting. Though they do not close their eyes, fish require sleep, and a lack of sleep contributes to the cumulative effects of chronic stress. Fish that are deprived of a natural cycle of light and dark do not perform as well as fish that are allowed to sleep in darkness. Indeed, fish deprived of darkness still sleep, although they do not derive anything near the benefits that fish with a night and day cycle do. The best light cycle is sixteen hours of bright light followed by eight hours of darkness. The longer photoperiod will ensure a healthy carpet of green algae and, therefore, lower nitrate levels, which will be discussed in detail later.
FILTRATION
Filtration occurs on two levels. The first is mechanical, the removal of visible impurities and particles by a mechanical baffle or screen. The second level of filtration is the chemical reduction of nitrogenous waste in the water. The nitrogenous waste products come from the proteins that the fish ingest. They are released into the water in the form of ammonia, which is reduced by bacteria living on the surfaces of the filter media. We will discuss this again, in more detail, in the section on the nitrogen cycle.
A wide variety of filters that are suspended from the aquarium, under gravel filters, canister filters, wet-dry filters bead filters, sponge filters, sand filters, and even algae filters.
Filtration also creates water current and oxygenates the aquarium water.
ULTRAVIOLET STERILIZATION
Ultraviolet sterilization can be regarded as another kind of filtration. It is done by pumping water into a cylindrical chamber that contains a high-intensity ultraviolet bulb protected by a glass sleeve. The intense ultraviolet rays shine through the water, and their wavelength actually disrupts the DNA of any microorganism passing through the chamber. The ultraviolet sterilizer does not perform any mechanical or chemical filtration but can be very useful in achieving water clarity by killing suspended bacteria and algae that cloud the water. Ultraviolet sterilizers are available in varying strengths. Stronger ultraviolet sterilizers kill more pathogens, including larger pathogens such as Ichthyophthirius multifilis (“ich,Eor white-spot disease).
For water clarification, including killing suspended green algae, the ultraviolet sterilizer is unsurpassed. Several manufacturers now offer small, aquarium –sized units.
With an ultraviolet sterilizer, you can achieve crystal Eclear water without the use of chemicals. In addition, ultraviolet sterilizers do not harm the green algae attached to the interior of the aquarium, which helps in nitrate control.
Ultraviolet sterilizer are also helpful in caring for sick fish, because they can decrease bacterial population in the aquarium and limit the spread of pathogens from one fish to another. I strongly recommend ultraviolet sterilization for clear, cleaner, healthier water.
WATER QUALITY
Maintenance of water quality is perhaps the most important aspect of
fish husbandry. The main parameters that must be controlled are ammonia, nitrite, nitrate, carbonate hardness, pH, oxygen, and temperature.
THE NITROGEN CYCLE
Ammonia, nitrite, and nitrate are intricately related in what is called the nitrogen cycle. An understanding and a mastery of the nitrogen cycle are probably the key elements of water–quality management. The nitrogen cycle refers to the process through which beneficial bacteria reduce fish wastes and excretions into environmentally harmless compounds. First they reduce ammonia into nitrite then nitrite into nitrite. Plants then use the nitrate as fertilizer, or the hobbyist reduces it through regular water changes.
Ammonia (NH3) is the primary waste product of fish, and the initial fuel of the nitrogen cycle. Vented waste makes up 25% of fishes ‘ammonia excretion; the other 75% of the fishes ‘ammonia excretion takes place via osmosis through the gills. Ammonia is not actively excreted, but leaves the fish because a higher level of ammonia exists in the bloodstream than in the surrounding water. When the water contains high ammonia levels, the ammonia does not leave the fishesEbloodstream and they die of ammonia poisoning.
Ammonia is removed naturally from the environment by beneficial bacteria of the Nitrosomonas species that lives on all underwater aquatic surfaces and in the filter. Nitrosomonas pares off ammonia’s hydrogen ions (H+) and replaces them with Oxygen (O2) molecules, creating a nitrite (NO2) molecule.
The need for oxygen in this reaction is illustrated in the following equation:
NH3 + (O2 required)¨(Nitrosomonas) NO2 + 3H +
Both ammonia and nitrite accumulation can be detected by simple water test kits readily available at your local fish store. A cycled tank should always have readings of zero for these two compounds.
As we have seen, the beneficial bacteria Nitrosomonas convert ammonia into nitrite. Nitrites are broken down by another beneficial bacteria, Nictrobacter is extremely sensitive to water quality. It will go on hiatus if the water is too low in dissolved oxygen, too warm, too cold, or if it has been treated with almost any additive, or medication, including salt. When the Nitrobacter stop or slow down, you can expect to see an accumulation of nitrite in the system. In addition, the conversion of nitrite to nitrite is only half as efficient as the conversion of ammonia to nitrite, which can also contribute to nitrite accumulation.
Nitrate is the final product of the nitrogen-reduction cycle. It is at this point in the cycle that reduced nitrogen can return to the food chain by becoming available to plants. Nitrate, in the presence of phosphates, makes a vitally important fertilizer for plant life of all kinds. Perhaps the most relevant plant in this regard is the simple algae. Many a garden pond has been clear all winter, and then in the spring, as the Nitrobacter bacteria “warm upEand begin to reduce the winter’s leafy wastes, the pond becomes pea- soup green. Fish tanks which have completed the nitrification cycle may also turn green at the six-week mark, as the ammonia finishes its path from nitrite to nitrite.
Again, nitrate levels can be determined through simple water test. It is recommended that you keep nitrate levels below 50 PPM, which you can do by regular water changes.
PH
The symbol pH stands for “potential of hydrogen E It is a measurement of the free hydrogen ions in a system. Neutral pH is assigned a numerical value of 7.0. As there are less and less free hydrogen ions in the water, that numerical value rises; as they accumulate, it drops. Water with a pH higher than 7.0 is called alkaline, and water with a pH lower than7.0is called acid. Aquatic life requires a pH from 5.5 to 9.5. The pH of fish (and human) blood, and coincidentally the ideal pH for Goldfish, is 7.4. The pH can be measured with a simple test kit.
Numerous factors influence pH. As we have seen above, Nitrosomonas bacteria produce hydrogen ion by stripping them away from ammonia to produce nitrite. These hydrogen ions accumulate in the water, resulting in lower pH. Minerals and carbonates tend to remove hydrogen ions from the water, which drives pH upward. Unsealed driftwood and other sources of organic molecules tend to bind up those minerals and carbonates, so that they can’t grab onto hydrogen ions; at the same time, these organic materials generate hydrogen ions as they decay, and these two factors combine to contribute to lower pH. Plants use carbon dioxide during their exposure to light, and this raises the pH. At night, plants give off carbon dioxide, which lowers the pH. Fish and bacteria all use oxygen and produce carbon dioxide twenty four hours a day, which lowers the pH. Combined, these biological processes tend to have the net effect on a fish tank of causing the pH to move downward into the acidic range. Fortunately, there are molecular”checks and balances against this effect.
CARBONATE HARDNESS
The molecule responsible for stabilizing the pH against these influences is called the carbonate molecule. A measurement of carbonate molecules is expressed as the total alkalinity (TA), or the carbonate hardness (KH).
Carbonates come from several places. In nature they come from the slow dissolution of natural minerals in rocks. In particular, limestone and gypsum are rich in carbonates, as are seashells and corals. As they dissolve, they release minerals such as calcium and magnesium, as well as carbonate molecules, into the water.
The carbonate molecule exists in a balance with the environment. When hydrogen ions become abundant, such as through biological processes, the carbonate molecules pick up the extra, which prevents the pH from falling. When hydrogen ions become scarce, the carbonate molecules will liberate some hydrogen ions. The net effect of the carbonate molecules on the water is to hold the pH at some constant level, which is why they are often called a buffer or buffering agent. Because of the importance of this buffering capacity of carbonate molecules, there is a benefit in having a quantitative measurement of carbonate activity in your aquarium water.
The carbonate levels in a system are measured by a test of the total alkalinity. Most major garden centers, pet shops, and pool-supply stores carry affordable total alkalinity test strips. Test results will vary depending upon regional conditions. For example, water in the eastern United States tends to have a total alkalinity below 50 PPM, while in the southeastern United States, the average total alkalinity is less than 30 PPM. In the southwestern United States, the water in the aquifer is mostly bedded in limestone or is derived from evaporation, and so the water has a very high total alkalinity of over 180 PPM.
A high total alkalinity E100 PPM and above Ewill keep your pH stable for along period of time. A low total alkalinity E50 PPM or under Ewill need to be remedied or you may have to cope with a sagging pH or sudden drop in ph. This will be discussed in more detail shortly. It is also possible to have a total alkalinity that is too high. A total alkalinity higher than 300 PPM may cause gill damage.
Not only do carbonate molecules occur in varying amounts in the environment, but they are also an exhaustible resource. When the carbonates are exhausted, the effect is a sudden drop in pH, which can and does kill fish.
A pH “crashEis a quick way to rid your tanks of all those messy fish. Here’s how to scenario often unfolds in the hobbyist’s tank. The water was changed two weeks ago, and at that time a satisfactory amount of carbonates existed in the system. The fish are fed daily, and the filter reduces their nitrogenous wastes. The hydrogen ions are bound up by the carbonates and all is well. The hobbyist is lulled into a false sense of security because the pH has been stable for weeks. Why check it now? Then the carbonates are finally exhausted, and overnight the fishesEcarbon dioxide production, the algae’s carbon dioxide production, and the reduction of the ammonia in the filter crashes the pH to 5.5 and the collection is all but lost.
I advise all hobbyists with water of low total alkalinity to use a good commercial buffer that will keep the pH at near neutral and the total alkalinity at about 100 PPM on a weekly basis.
GENERAL HARDNESS
General hardness (GH) is a measure of all minerals, including carbonates molecules. If you subtract the KH (carbonate hardness) from the GH (general hardness), you will have an estimation of the mineral content in the water. Water with a higher mineral content is commonly called hard, while that with a low mineral content is called soft. In nature, minerals such as calcium and magnesium (which come from calcium and magnesium carbonate) have no effect on the pH of a system. As a result, it is possible to have very hard water (water of high mineral content), but have very little carbonate activity Eand consequently, a lower pH. As is the case with carbonate hardness, a general hardness of over 300 PPM is harmful to Arowana.
OXYGEN AND CARBON DIOXIDE LEVELS
Oxygen is soluble in water, but not very well. Dissolved oxygen may range from 0 PPM. For keeping fish, concentrations of 8 PPM and a above are desirable.
The key to oxygenation is to increase surface contact of air and water. One common misconception is that the air bubbles of an air stone are adding oxygen to the water. They are, but only to the extent that on the way to the surface they push a column of tank water into contact with the air at the water’s surface. We can increase oxygenation just as effectively with a submersible water pump by resting the pump on the tank bottom and aiming the output at the surface. In this manner, you can generate tremendous exposure of water to air at the water surface and gas exchange.
Oxygen is very important to the nitrifying bacteria of the filter because oxygen is integral to the production of nitrite from ammonia. (See the discussion of ammonia above). Warm water carries less dissolved oxygen than cold water, a fact that is significant to the health of both your fish and your filter. As mentioned earlier in this book, keeping Arowana at high temperatures ( above eighty degrees ) increases the oxygen demand of the fish and filter bacteria, while at the same time warmer temperatures actually reduce the ability of the water to provide the much Eneeded oxygen. Cold water, on the other hand, carries a near Esaturation value of dissolved oxygen without much circulation or surface agitation at all. Why is this relevant? Because when considering certain water treatments that consume dissolved oxygen Esuch as potassium permanganate and formalin Eyou must remember that cold water is better than warm water.
The fact that cold water carries more oxygen also means that when fish are to be shipped or transported from one place to another, whether across oceans or to the local vet, water of a temperature less than seventy degrees is preferable.
In heavily planted aquariums, dissolved oxygen follows a daily cycle. By day, plants engage in photosynthesis and produce considerable amounts of dissolved oxygen. In some cases you can actually see tiny bubbles rising from the leaves. At night, the plants grow and respire. They reverse their metabolism and produce carbon dioxide and take in dissolved oxygen. The miniscule algae are no different from more complex plants in this regard. As a result, a heavily planted tank or a tank with a lot of suspended green algae may have low dissolved oxygen levels at night.
Carbon dioxide is produced by the respiration of both plants and animals. When you exhale, you produce carbon dioxide. Carbon dioxide levels can exist independently from the oxygen concentration in water. For example, water may have large amounts of oxygen and carbon dioxide at the same time.
In water, carbon dioxide readily converts to carbonic acid, which in turn tends to lower the pH. A large number of fish in a small tank with minimal circulation and surface agitation may actually accumulate sufficient carbon dioxide to lower the pH. On the other hand, removal of carbon dioxide by increasing surface exposure and gas exchange will remove the source of carbonic acid and may raise the pH.
Remedies to carbon dioxide accumulation include increasing surface exchange with air stones or pumps. As suggested earlier, raising the dissolved oxygen of the system does not decrease the carbon dioxide levels, but increasing surface exchange of air and water is a step toward maximizing both.
MAINTENANCE SCHEDULE
Water quality is not a guess. The hobbyist has complete control over water quality and can measure water quality with simple tests. The most important tests are for ammonia, nitrite, nitrate and pH and a test for total alkalinity is also useful. Measure all of these parameters daily in new system. In mature system that have been stable for some time, measure ammonia, total alkalinity, nitrite, and nitrate weekly and pH daily.
Regular water changes are an important way to maintain water quality. When water quality is poor, you should perform daily water changes and suspend feeding until the problem is corrected. In mature systems, perform a 10% to 20% water change every week. At minimum, you could change 20% to 30% every two weeks. Unless your tank is very sparsely stocked, you will notice that if you neglect the above schedule, at best your fish will not flourish, and in the worst case, they will die.
Use of a buffer on a regular basis is your best hedge against a falling total alkalinity and falling pH. The two parameters are related, as we have seen above. As a routine, the hobbyist with low total alkalinity should apply a buffer according to manufacture’s directions once per week. Test your water Eand remember, it may change through the seasons and over time Eto determine if the buffer is a wise or necessary addition. As a rule, use a commercially prepared buffer whenever the total alkalinity is below 30 PPM.
Finally, to preserve water quality your filtration system should have regular maintenance. Wring out sponge filters every three weeks under normal loading. Backwash bead filters once per week under normal loading. Open and rinse canister filters once every six weeks. Rinse power and hang –on filter pads every three weeks under normal loading. With under gravel filters, suction Eclean half the tank’s gravel every ten to fourteen days, alternating the sides weekly.