Chemical filters are needed for koi pond

It was not easy to define a chemical filter, because at first glance almost the same function with a mechanical filter. The difference lies in the particle size in the "working on", therefore it may be said that the chemical filter is a mechanical filter that works on a molecular scale. As previously disclosed, the mechanical filter works with manangkap suspension, then the chemical filters work by capturing soluble materials, such as: gas, dissolved organic matter, and the like. This mechanism is done with the help of the media in the form of activated charcoal filters, ion resin, and zeolite, or through water fractionation.Chemical filters can perform its functions in three ways, namely: (1) Absorption, (2) ion exchange, and (3). SorptionAbsorption (Absorption).Absorption is a process in which a particle trapped into the structure of a medium and as though a part of the overall media. This process is found mainly in the activated carbon media. Activated carbon has a pore space is very much of a certain size. These pores can capture very fine particles (molecules) and trap him there. As time passes these pores will eventually be saturated with particles so fine that will not work anymore. To a certain extent some types of activated charcoal can be reactivated again, though not infrequently suggested to be disposable. Reactivation of activated carbon depends on the previous activation method, therefore it should be noted that information on product packaging.In general, carbon / activated charcoal is usually made from coconut shell charcoal by heating at a temperature of 600-2000 ° C at high pressure. In this condition will be formed fracture-fracture (cavity) is very smooth with a number of very much, so the charcoal surface area becomes large. 1gram activated carbon, generally has a surface area of ​​500-1500m2, so it is very effective in capturing particles are extremely fine-sized 0.01-0.0000001 mm. Activated carbon is very active and will absorb whatever is in contact with carbon, both in water and in the air. If left in the open air, it soon will absorb fine dust contained in the air (pollution). Usually within 60 hours of activated carbon are widened saturated and no longer active. Therefore, typically activated charcoal in containers in airtight packaging.Sorption (adsorption).Sorption is a process where a particle "stuck" on a surface as a result of the "difference" weak charge between two objects (Van der Waals forces), so that eventually will form a thin layer of fine particle-particle on the surface. Carbon surface is able to attract such an organic molecule is one example of sorption mechanisms, as well as which occurs in water-air interface, ie the mechanism that occurs in a protein skimmer. Organic molecules are polar so that one end will tend to be attracted to water (referred to as hydrophilic / water loving) while the other end is hydrophobic (hates water). Surface active molecules such as these will be interested in the water-gas interface on the surface of air bubbles, so that the molecules will form a thin layer of foam in there and forming / foam. In a protein skimmer; when the air bubbles leave the water to the bin foam, air bubble will collapse and eventually organic materials will be left on the bin foam is concerned.Ion exchangeIon exchange is a process in which ions are terjerap on a surface filter media exchanged with other ions in the water. This process is made possible through a phenomenon of attraction between the charged surface of the media with these molecules are polar.When a charged molecule touches a surface that has an opposite charge then the molecule will be bound chemically to the surface. In certain conditions these molecules can be exchanged its position with other molecules that are in water that has a higher tendency to be bound. Thus, the exchange process can occur. Media that can perform such an exchange process include zeolites (either natural or artificial) and resin.Exchange process which takes place in general follow certain rules. namely:The first cation-cation with a valence greater shall be exchanged prior cations with lower valence. 
Second, the cation concentration is highest in the aquarium will adsorb the valence lebihkecil telebih first though. For example in the above case, if the concentration (amount) of ammonium far more than the premises of iron and calcium, then in accordance with rule 2, the ammonium will tend in jerap first.With the above processes the chemical filter can be applied to "purify" the water of paritkel molecular-sized particles that can not be processed by mechanical or biological. Some things that can be removed by chemical filters include toxic effects, hardness, color and dissolved organic particles.