Article from NAGA MERAH book

[JD Winata]

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 fishesEbloodstream 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 upEand 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 “crashEis 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 fishesEcarbon 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.

[JD Winata]

Advance application:

HARDNESS AND pH VALUE

Many aquarists invest substantial effort in trying to modify the pH of their tap water. Unless this endeavor is preceded by a successful attempt to alter its hardness, it is at best an exercise in futility and, at worst, is likely to prove a positive hazard to their fish. With rare exceptions, the dominant dissolved chemical substance in fresh water is calcium (more rarely, magnesium) carbonate. The relative abundance of carbonate ion largely determines the pH of water. Furthermore, its natural buffering capacity sets precise limits on the extent to which the pH can be permanently altered. Thus, aquarists find it useful to ascertain not only the total or general hardness/GH , but also the carbonate hardness/KH – a measure of the amount of dissolved carbonate present in the water supply. The ability to measure accurately both pH and hardness is essential to any attempt to modify the chemical composition of aquarium water; reliable test kits are essential to the success of such efforts.

MAKING WATER SOFT

Water with an elevated carbonate hardness is extremely resistant to acidification. It is possible to push its pH into the acid range using sodium biphosphate, but within a few hours it will return to its original value. The pH level of such carbonate-rich waters can be permanently lowered only by ‘breaking’ the natural buffering system. You can remove dissolved carbonates by passing the water through a selective ion – exchange resin, or a reverse osmosis treatment unit. Recent developments allow the addition of a simple liquid, which reduces the hardness and keep up pH levels.
Once this has been done, it is a simple matter to lower the pH by progressive addition of commerciality available tannic and humic acid concentrates, or by filtering it through acidic peat. Alternatively, you can by pass the problem of hard tapwater completely by using commercially available demineralized water when setting up your tank Adding 1 gm of aquarium salt per 40 litres(approximately 1 level teaspoon per 10 gallons) will raise its concentration of ‘physiological ions’ to a level that will support fish life without adding to its carbonate hardness. It can then be acidified using either of the techniques previously suggested.
Demineralized water is not cheap, but the cost of it may be acceptable on a one-time basis when setting up an aquarium. However, few aquarists will be willing to buy it in sufficient quantities to carry out regular partial water changes. Techniques exist to reduce the frequency of such changes, but there is no way to eliminate them entirely from a workable nitrogen cycle management programmed. It is clear, therefore, that if you wish to keep soft water cichlids in an area with hard tapwater, you would do well to invest in a water treatment system that will supply water of appropriate chemical composition in quantity an at reasonable cost.
In many parts of the world, homes are equipped with commercial water softening systems that use selective ion exchanges resins. These materials substitute sodium (Na+) for calcium (Ca++) and magnesium (Mg++) ions, and chloride (Cl--) for carbonate (CO3--) and sup hate (SO4--) ions.(The positively charged ions are called cat ions and the negatively charged ions are known as anions). Water treated in this way is suitable for most domestic uses, but less acceptable for fish keeping purposes. Ion-exchange resins exist that will completely demineralized tapwater. Such resins substitute hydrogen ions (H+) for dissolved cat ions and hydroxyl ions (OH-) for dissolved anions. These resins are not generally employed in home water treatment systems, since they must be regenerated with strong acids and bases, a hazardous and uneconomical procedure.
The most attractive available to aquarist for softening hard water is a small reverse osmosis water treatment unit. Such systems remove minerals from solution by passing tapwater under pressure through membranes selectively impermeable to dissolved substances. Depending upon the level of use – and on the concentration of the dissolved substances they are called upon to remove –such membranes enjoy a working life of there months to a year, and replacing them is a simple matter.
Reserve osmosis units are more compact and efficient than those relying upon selective ion-exchanges resins. They are also much safer, as they do not require treatment with corrosive acids and bases to regenerate their active components. Commercial units capable of producing about 100 litres (22 lmp. Gallons/25 US gallons) of demineralized water daily are available at considerably less cost than a water treatment system based on selective ion-exchanges resins. The initial outlay may still seem high, but given the cost of bottled demineralized water, such a unit will pay back its purchase price quite rapidly.

Ammonia, nitrites and nitrates.
Fishes obtain the energy necessary to sustain their metabolisms by ingesting and breaking down organic compounds. The breaking down of fats and carbohydrates produces waste products in the form of water and carbon dioxide. Protein digestion yields both of these compounds and, ultimately, nitrogen gas. However, the digestion of protein foods by a fish is only the first step in a long and complex process that completed in the surrounding environment.
Two the intermediate products of this process, ammonia and nitrite ion, are known to be toxic to fishes and other aquatic organisms. Ammonia exists in two distinct forms: highly toxic, electrically neutral dissolved ammonia (NH3), and the harmless, positively charged ammonium ion (NH4+). The percentage of each chemical substance depends upon the pH value of the aquarium water. The amount of toxic ammonia increases as tank conditions become more alkaline.
While most fish keepers must worry about losing fish from ammonia poisoning, such an eventuality is much less likely to befall aquarists who work with riverine species. However, nitrite is almost as dangerous under freshwater conditions and, unlike ammonia, the risk it poses to aquarium fishes is not a function of pH. Long –term exposure to high concentration of a third nitrogen cycle intermediary – nitrate (NO3) – is suspected of having a harmful effect on both growth and the readiness of a wide selection of ornamental fishes to breed in captivity. The secret of successful cichlid husbandry is to keep concentrations of all three dissolved metabolites (literally substances produced by metabolism) as low as possible.
Regardless of where they originate, Arowana do not relish long – term exposure to dissolved metabolic wastes. Species native to the nature river and those inhabiting forest streams or the permanent rapids of large rivers cannot tolerate even brief exposure to either ammonia or nitrite. Neither substance ever builds up to physiologically stressful concentrations in their native habitats and so these fishes have lost any ability their ancestors might have possessed to cope with such stress. Even less than lethal long-term exposure to levels of these substances erodes their natural ability to resist disease and typically leads to death from systemic bacterial infections such as’ Digestion bloat’. Fish from seasonally variable riverine habitats are often exposed to higher nitrite and nitrate concentrations for brief intervals during the dry seasons. They are thus better able to tolerate short-term exposure to these pollutants incapacity, in capacity, but even they cannot prosper without due attention to nitrogen cycle management.

Biological filtration
The nitrifying bacteria that convert ammonia to nitrite and thence to nitrate are present in any aquatic habitat with measurable dissolved oxygen levels. The object of biological filtration is to create an environment that supports the largest possible numbers of these bacteria and allows them to metabolize nitrogenous wastes with optimum efficiency. The simplest way to create such conditions is to pass well-laden water through a porous medium that favours colonization by nitrifiers. It is essential to remember that the active element in a biological filter is its bacterial flora. Experienced aquarists often introduce the appropriate organism to a new filter bed to accelerate its establishment. Bacteria starter cultures serve this purpose and are commercially available. These cultures rapidly increase in number and significantly reduce the filter-maturing timescale. Adding a handful of ceramic rings from a functioning bed to a new canister filter or merely wetting a new sponge filter in an established aquarium works just as well. Remember, too, that such a filter cannot function at peak efficiency until its bacterial population is fully established. This is a good reason for adding a few fish at a time to a newly set-up aquarium, otherwise the waste load produced by the newly introduced fish will outstrip the growth rate of the bacterial population and lead to an upsurge of toxic byproducts. Marine aquarists have learned to stock a tank initially with one or two organisms that are tolerant of temporarily high levels of ammonia and nitrite. Once the filter is fully established, as indicated by a gradual drop in the nitrite level, additional fishes can be added gradually. This minimizes the likelihood of losing fishes during the filter’s running –in period. Arowana keepers are well advised to adopt this prudent approach, notwithstanding the more robust constitutions of the fishes in their charge.
For community tank for more than 2 arowana kept together ,when stocking a newly set-up aquarium in this manner, take care to introduce the least aggressive fish first and the most aggressive last. The longer a arowana occupies a tank, the more its aggressive tendencies will be reinforced. If the most belligerent of a community’s intended residents is the first to be added to the tank, it will quickly come to regard it as his own and can be counted on to harass any subsequent additions. Less aggressive species bear up poorly in the face of such persecution. Even if they are not killed outright, the constant behavioural stress to which they are exposed makes them extremely susceptible to systemic bacterial infections.
Finally, never forget that a biologically active filter bed has a finite waste processing capacity, determined by the metabolic rate of its nitrifying population. This in turn is influenced by environmental factors, such as water temperature and dissolved oxygen concentration. The stocking rates suggested here tend to err on the side of caution, so be prepared to experiment cautiously in order to determine the full potential of your system. However, the bottom line is simply this: There is not always room for one more in an aquarium! The temptation to disregard this axiom is pervasive and powerful; the consequences of succumbing to it are inevitable and often painful, as most novice aquarists learn to their cost.


The importance of water of changes
In theory it is possible to avoid physiological stress caused by a build up of waste products solely by installing efficient biological filtration in the aquarium. This approach founders on the harsh reality that cichlids are large fishes with healthy appetites and produce a great deal of both liquid and solid waste. Furthermore, many Arowana exist at high population densities in nature and experience has shown that one way to minimize unwanted aggression is to house these species in a comparable fashion in captivity. This adds further to the waste load generated by a cichlid community. Efficient biological filtration unquestionably plays an important role in nitrogen cycle management in cichlid aquarium. However, it cannot be expected to do the job unaided and a programme of regular partial water changes is thus an indispensable element of successful cichlid husbandry, regardless of species.
Arowana appreciate partial water changes of 30-50 percent every 7-10 days. In heavily stocked aquarium you will need to increase the frequency of the water changes and the amount of water replaced. Arowana, in particular, seem to relish a regular replacement of up to 85 percent of their tank’s volume. However, Arowana respond less favourably to large-scale water changes.. Fortunately, most of these Arowana will thrive as single pairs and the waste load produced in such a lightly stocked tank is unlikely to strain the capacity of a well-established biological filter. Wholesale water replacement should be unnecessary; it is enough to change 10-15 percent of the tank’s volume every 14-21 days to keep dissolved metabolites at acceptable levels. Changing the same volume of water in a more densely populated Arowana community tank every 7-10 days serves the same purpose without distressing the fishes.
Always ensure that the temperature of freshly drawn water is within 1○C(2○F) of the water in the tank to which it is added. It must also have the same chemical make-up. This condition is clearly easier to meet if your fishes prosper in unmodified tapwater.
As a rule, the chlorine content of most municipal water supplies is not high enough to threaten the well-being of adult Arowana. Nor is there any evidence that the chlorine concentration in tapwater poses any risk to a biological filter bed. However, it is sensible to use a proprietary dechlorinating agent when making water changes in fry tanks or those containing adults species.
Chloramine is quite another story. This compound of ammonia and chlorine is more persistent than elemental chlorine and less easily neutralized. It is a fairly simple matter to break the bond between the two substances and neutralize the resulting free chlorine with a double or treble dose of a commercial dechlorinating agent. However, there then remains the task of removing the toxic ammonia that remains behind.
The problem of residual ammonia is obviously more important to keepers of Arowana than to those who maintain riverine species. Under the slight acid water conditions demanded by the Arowana, much of the ammonia will exist in the toxic, electrically neutral form (NH3), wheareas under neutral to acidic conditions, the harmless, positively charged ammonium ion (NH4+) will predominate. A fully established biological filter can degrade small quantities of ammonia efficiently, so one way of coping with the presence of chloramine is to reduce the volume of water replaced at each change and to increase the frequency of the changes. Alternatively, a proprietary single- step chloramine neutralizing agent, used according to the manufacture’s instructions will tie up the ammonia in a harmless organic complex that can subsequently be degraded by bacterial activity.
Aquarists who live in areas with a severe winter climate may have to take into account the risk of gas embolism when making water changes during cold weather. Sometimes known as gas-bubble disease, the condition is caused by the supersaturation of dissolved gases in very cold water. As the water warm up, it loses its capacity to hold the dissolved gas. The result is an eruption of bubbles over every solid surface that the dissolved gas contacts as it leaves the water. When such bubbles form in the superficial tissues of a fish’s skin, or in its gill filaments, they can cause serious damage. In small fishes it can often prove immediately fatal, in those species large enough to survive the initial trauma it can lead to secondary bacterial infections.
To test for gas supersaturation draw a glass of cold tapwater and let it sit at room temperature for fifteen to twenty minutes. The presence of air bubbles covering the interior of the glass indicates the presence of dangerous concentrations of dissolved gas in the water supply. The only way to completely eliminate the risk this condition poses to the fishes is to draw water a day before making a water change and allow the dissolved gases to effervesce as they reach room temperature. However, this approach is not always practical for aquarists, since it entails storing a considerable quantity of water .
Refilling a tank through a mist nozzle as used by gardeners will dissipate most dissolved gases before they enter the tank, but this is a time consuming process, as the flow of water through such a nozzle is very slow. A more realistic alternative is to restrict water changes to 10 percent of a tank’s volume during the winter months and compensate by increasing their frequency.

Remember to disconnect the tank’s heater when making a water change.
If the water level drops too far, the heater tube will seriously overheat and almost certainly crack when it comes into sudden contact with cooler replacement water. Many experienced aquarists also believe that it is not advisable to combine large-scale water changes with the replacement or cleaning of the tank’s filter medium. Insofar as the presence of organic matter tends to neutralize free chlorine, there is some truth in this as far as a mechanical units is concerned. However, the function of a biological filter will not be affected if the medium is rinsed in warm, rather than hot, tapwater.
Most of the mess and bother associated with replacing water are eliminated if one uses an automatic water changer. This apparatus – part siphon – powered gravel cleaner, part water bed pump- attaches directly to the tap and, with a flip of a control knob, changes from a powered siphon to a hose. Thus you can combine a water change with the removal of waste from the substrate, another important aspect of nitrogen cycle management.
Breeders may find the action of an automatic water changer a bit too powerful in a tank containing newly mobile fry. It is a good idea to collect the waste water from a fry tank in a bucket before pouring it away, thus allowing any wayward fishes to be rescued and returned to their tank. A close encounter with an automatic water changer would result in a free one-way tour of the local waste treatment plant. However, there should be no problem finding an alternative means of cleaning a fry tank. The many aids available to the fish keepers today have transformed the nature of time – consuming, often tedious, but essential chores. The efficiency with which you can carry out routine maintenance, will in turn increase your success in the hobby and contribute to your enjoyment of it.

[hengky]

Congratz for your upcoming book...cant wait for it.

When will the overseas readers get to get ahold of the book?

[JD Winata]

It took a while to wrote all of them into one book , seems to complicated ,but its contain all you need to know and what you never know before

[Buddy]

very interesting topic...I'll try to understand more about the Water and the environment 4 keeping aro...

[JD Winata]

The LAST arowana book from Indonesia

[jomblo]

Bakal jadi buku pamungkasnya peraroan, gak sabar nunggu launchingnya april ini

[artdisc]

thanks alot MR JD it make me seeing more of horizon to the real aro secret

[nin0]

Really looking forward to it... When will it be launched?? Where?

[azura]

Originally Posted by nin0

Really looking forward to it... When will it be launched?? Where?

soft launching at n1wan's pro shop on 14 April

[dony]

ck ck ck ... better if I read the book directly ..

[arozone]

I am really looking for NAGA MERAH Book.,and can't wait !!

[jonathan]

one thing,....how much?

[kaer]

Great..., i'm sure i'll buy the book, mr hans...
of course IER 2

[pdk]

great info and thanks for taking the time to make a book...hope to learn more when the book is available