LET’S TALK ABOUT FILTER AND WHY IT IS NECESSARY Physical Filtration (general) Sometimes we forget that fish kept in an aquarium are confined to a very small quantity of water as compared to their natural habitats in the wild. In the wild, fish wastes are instantly diluted. But in an aquarium, waste products can quickly build up to toxic levels. These waste products include ammonia released from your fishes' gills fish poop, and scraps of uneaten food. The food and the poop will also eventually decay, releasing ammonia. Even small amounts of ammonia will kill your fish. Obviously, the more sources of fish waste, the quicker and greater the ammonia problem. A small heavily-fed tank with lots of large fish will have much more ammonia than a large tank with one seldom-fed small fish. But for both these cases you need some form of aquarium filtration to control the toxic ammonia. Some aquarists try to control ammonia levels exclusively by changing the water. This is helpful, but impractical because of the frequency and size of the water changes required. Fortunately, there is an easier way! In fact, the world is full of bacteria that want nothing more than to consume the ammonia and convert it into less toxic substances. For many aquarists, this process occurs without their knowledge or help. However, the smart aquarist will learn how to take advantage of these beneficial bacteria by maximizing its growth. When you start a new fish tank, colonies of beneficial bacteria have not yet had the chance to grow. For a period of several weeks this is hazardous to fish. You must gradually build up the source of ammonia to allow time for the beneficial bacteria to grow. Well you can go to the local pet store and buy many products, which are especially made for fast biological bacteria growing, and remember to buy only one small salt fish. Put the product in tank by using the instructions and put a fish in for at least two weeks. This is called "cycling" your tank. Remember that the bacteria break down the ammonia into substances (first nitrite, then eventually nitrate) that are merely less toxic, rather than non-toxic. Many fish can tolerate reasonably high levels of nitrates, but over time the nitrates will accumulate until them, too, become toxic. Also, because nitrate is a fertilizer, high nitrate levels can lead to excess algae growth.Well we will discuss later how to "fight" with nitrate... So, the question is how can I build the physical filter? Filtration Biological filtration is the term for fostering ammonia-neutralizing bacteria growth. It is so important to the health of your aquarium that we should look more closely at how this process works. (There are other types of wastes that can cause problems, but the regular partial water changes needed to control nitrates are typically enough to control other forms of waste as well.) Mother Nature provides several types of bacteria that break down ammonia into progressively less toxic compounds, nitrite and nitrate. These bacteria are not harmful and are quite abundant in nature. They are so common that we do not need to add them to our aquariums; nature does it for us. In the presence of ammonia and oxygen these bacteria will naturally multiply. The bacteria attach to the tank, rocks, gravel, and even tank decorations. Note that we have not yet said anything about a physical filter. This is because bio-filtration bacteria require only 1. A surface upon which to attach, 2. Ammonia for food, and 3. Oxygen-rich water. This sounds so simple; why do we need a physical filter? Actually, if you limit the amount of fish to what the natural bio-filtration can handle, you do not need a physical filter. Unfortunately, you cannot support very many fish with only the natural bio filtration. In the last few decades, the hobby has seen many new types of biological filters invented which can vastly increase the capacity of the bacteria colony to provide biological filtration to your aquarium. In essence, all of these types of filters provide additional surface area for bacteria attachment and increase the available oxygen dissolved in the water.
Biological Filter types
Sponge filters Sponge filters provide an efficient and cheap form of biological filtration. Water is forced through porous foam, either by a power head, or air bubbling through an airlift tube. Water flowing throw the sponge allows the growth of a colony of beneficial bacteria which neutralizes toxic ammonia. One style of sponge filter uses two sponges attached to one lift tube. These have the advantage that the sponges can be cleaned one at a time, reducing bacterial loss. Also, one of the sponges can be removed and transferred to a new tank, bringing with it a colony of beneficial bacteria, and thereby "jump starting" the cycling of a new tank. Some enlightened fish stores sell these double sponge filters to beginner customers when they sell a tank kit. They take one of the new sponges out of the "box" and swap it for an old established sponge in one of their tanks in their store which is carried home in a plastic bag.
Mechanical filtration
Mechanical filtration Remember that ammonia comes directly from the gills of your fish, but also from decaying fish poop and food scraps. If you can mechanically filter out the poop and the waste food before it gets a chance to decay, you can be a step ahead in the game. Not to mention that these wastes are ugly and can detract from the beauty and enjoyment of your aquarium. Simply stated, mechanical filtration is the straining of solid particles from the aquarium water. Mechanical filtration does no directly remove dissolved ammonia. Most common mechanical filter media do not remove microscopic bacteria and algae from the water. Neither will mechanical filtration remove and solids trapped by gravel, plants, or decorations. Some people install circulation pumps, known as wave makers, to improve the chance of catching solid wastes in the mechanical filter. The four most popular mechanical filtration media are sponges, paper cartridges, loose and bonded floss media which are reusable to different degrees. Clean paper cartridges have the smallest openings and clean bonded floss has the largest openings. Clean sponges and clean loose floss fall somewhere between. A filter media with small openings catches finer particles, but clogs faster. Also, as a rule, a physically large filter area will clog more slowly than a small filter. As the filter media gets dirty it will trap smaller and smaller particles. At some point the media is so clogged that it will not pass water.
SUMMARY: A good mechanical filter is one that traps enough solids to keep the water clear without plugging too often.
Chemical Filtration Chemical Filtration Chemical filtration, in short, is the removal of dissolved wastes from aquarium water. Dissolved wastes exist in the water at a molecular level, and fall into two general categories, polar and no polar. The most common chemical filtration method involves filtering the water through gas activated carbon which works best on the no polar wastes (but also removes polar wastes). Granular activated carbon is manufactured from carbon, typically coal, heated in the presence of steam at very high heat. This process causes the carbon to develop huge numbers of tiny pores, which trap no polar wastes at the molecular levels by means of adsorption and ion exchange, and removes heavy metals and organic molecules, which are the source of undesirable colours and odours, through a process known as molecular sieving. The best activated carbon for filtering water is made from coal and is macro porous (having larger pores). A good macro porous activated carbon feels light (not dense) and fizzes and floats when initially wetted. Activated carbon intended for removing wastes from air (such as odours) are commonly made from coconut shell and are micro porous. Carbons for filtering air feel denser. Some people with reef aquaria are concerned about phosphate leaching from activated carbons. As a rule, buy only carbons made by reputable aquarium supply companies which have been acid washed during manufacture to minimize ash content. Carbons low in ash also helps reduce the chance of undesirable pH shifts. Low ash carbons typically have lower phosphate leaching levels too. The phosphate in activated carbon stems from the fact that carbon is manufactured from coal, which was once living plant matter. All living matter is high in phosphates. The leaching of phosphate from activated carbon is known to be high initially and to decrease over time. This problem can be mitigated significantly by pre-soaking your activated carbon for a few weeks before use. Some people are concerned about activated carbon removing trace elements required by plants and invertebrates for healthy growth. Trace element depletion is a problem in planted aquaria and mini reefs, with or without activated carbon. The potential benefits of activated carbon are great enough that on whole you will be better off using it. If trace element depletion is a worry, use a trace element supplement in conjunction with the activated carbon.Activated carbon cannot be rejuvenated outside a laboratory, but fortunately, it is cheap enough to use liberally. Always wash your carbon before use to remove the dust that accumulates during shipment. Advice on how much to use vary, but smaller amounts changed more frequently seem to work best. You probably want to experiment, but 1/2 cup per 20 gallons water, changed monthly is a good starting point. In summary, activated carbon is an excellent, cheap and effective filtration method which is highly recommended for all aquaria. A variety of special chemical filtration media have been developed to remove specific chemicals.
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