The differences in mechanical, biological and chemical filtration of the aquarium. The most common types of filters and filter materials, structural features
There are a large number of filter models from quite budget to very expensive. In order not to get confused in this variety and to choose the most suitable model for a particular aquarium, you need to know about the types of filtration and the most popular types of filters, each of which has its own advantages and disadvantages. And now in order …
The filter is designed to remove various contaminants by passing water through one or more layers of filter material. The visible result of the filtration system is clean, odorless water and small particles of debris, however, much more important processes take place at the microscopic level and are associated with the activity of the colony of beneficial bacteria that eventually colonize the surface of the filter material. Water is inevitably polluted by hazardous substances formed during the decomposition of organic waste (food remains, fish excrement, etc.), and these useful tiny helpers process them into safer ones. Thus, water purification with a filter allows you to maintain optimal living conditions for fish in a closed aquarium ecosystem.
Filters are divided into two large groups according to the method of passing water through the filter material. The first is with an electric pump. The second is through the flow of air bubbles, which entrains water, thus drawing it into the filter. Let’s call them electrical and air.
Classification of Fish Tank Filters
Electric filters have a huge number of modifications that can solve any problem in both amateur and professional / commercial aquarism. The advantages of this group include high performance, versatility (can provide all types of filtration) and a wide range of applications (available for aquariums of all kinds). They are divided into internal and external, that is, they are located inside the aquarium or outside.
Among the air filters, the most widely used are bottom and airlift filters. Their advantages include simple construction, low cost and low power consumption. And the disadvantages – a modest performance, so they are not recommended for use in large aquariums. They are located exclusively inside aquariums.
Types or methods of filtering
There are three main types (methods) of filtration: mechanical, biological and chemical. It is worth noting that even the simplest filters (electric or air) carry out two types of filtering at once – mechanical and biological, and more expensive and all three, therefore for a home amateur aquarium it is enough to install only one filter that is suitable for design and cost. all water treatment tasks.
1. Mechanical filtration
Purification of water from suspended solids (turbidity from new soil, fish excrement, pieces of dead leaves, not eaten remnants of food, etc.) using porous materials in the filter. The criterion for the quality of mechanical filtration is the transparency of the water.
2. Biological filtration
Purification of water from toxic nitrogen compounds (ammonia, ammonium, nitrite) arising in the process of fish life, in part about this mentioned above. The processing of hazardous substances is done by beneficial bacteria that naturally inhabit the surface of filter materials or special carriers provided in the filtration system, for example, bio-balls, sponges, etc.
3. Chemical filtration
Water purification from dissolved organic compounds such as ammonia, methane, hydrogen sulfide, drugs used for the prevention and treatment of fish, etc. Partially duplicates the work of biological filtration, but unlike the latter has a wider range of applications and is based on chemical reactions between organic compounds and special fillers (activated carbon, zeolite, phosphate absorbers) in the filter material. A side effect of some fillers is a change in the hydrochemical composition of the water.
What should you pay attention to?
The main parameters of the filter are the volume of the filter medium and the capacity (the rate at which water is pumped through the filter) – measured in terms of the number of liters per hour (l / h).
The performance of the purchased filter should correspond to the size of the aquarium, you should not prefer too large filters, because they create a strong flow in small aquariums.
A filter with a capacity of 300 l / h will completely pass all the water in a 600-liter aquarium in two hours, but in a 50-liter aquarium it will take about ten minutes. From the point of view of fish, this is the same thing as living in a washing machine.
However, an insufficient rate of flow of water through the filter may cause the water to become turbid, and an insufficient volume of filtering medium will cause the filter to quickly clog, so the best option is a filter with adjustable power.
What types of filters are there?
All the variety of filters can be divided into several types listed below. They are arranged in a hierarchy, the first are the most simple and cheap, close the list of the most technologically advanced and effective, but expensive.
Sponge air lift filter
Consists of a perforated plastic tube on which one or more sponge cartridges are attached. Through the lower part of the air is supplied, which rising, captures with water, thereby creating cravings. Water enters the tube through the sponge, leaving a variety of garbage on it. It primarily performs biological filtration and, to a lesser extent, mechanical filtration, since the porous structure of the sponge creates a huge area for colonization of useful bacteria. Many aquarists constantly make the sponge filter work somewhere in the corner of the common aquarium, thereby maintaining the biological maturity of the sponge, so that later, when necessary, use it in a quarantine or spawning aquarium. Read more in the article "Aerlift filter with a sponge as the best tool for biological filtration."
First of all it is intended for biological water purification. Cheap, durable, virtually maintenance free and invisible in design. However, there are a number of specific features that make it a poor choice for a novice aquarist. Since the substrate of the aquarium is important as a filter material, it is important to choose the size of the soil particles and its depth correctly. In addition, design objects and dense roots of plants will prevent the passage of water, forming "dead zones", where silting will occur with unpleasant consequences in the form of bubbles of methane or hydrogen sulfide.
Internal filter cups
One of the most popular filter varieties due to the excellent price / performance combination. They perform both mechanical and biological filtration, come in a variety of sizes, and can be installed both vertically and horizontally. The best choice for an amateur aquarium is small (up to 100 l.) And medium (up to 200–300 l.) Sizes.
As the name implies, they are suspended from one of the walls of the aquarium. Suitable for tanks from 20 to 300 liters, capable of performing all three types of filtration. Easy to operate, filter cartridges are located outside and are easily accessible for replacement or cleaning. Purified water returns as a kind of waterfall, rather than a stream of water like a cup filter, thanks to which the internal flow in an aquarium is minimized, which is useful when keeping some species of fish coming from stagnant bodies of water such as the Killy and Labyrinth Fish. There is a slight drawback of the filter mounted because of its design – the aquarium should always be more than 2/3 full, otherwise the water intake tube will not reach the water or it will not be submerged enough to reduce cravings and performance.
Irrigation or irrigated filters
Mainly used by professional aquarists in commercial aquariums. The main task of such filters is biological treatment; however, manufacturers often provide equipment for mechanical and chemical cleaning. The filters are located outside, the design provides several compartments usually filled with special bio-balls, which are constantly irrigated with incoming water and thus create the most comfortable conditions for the development of a colony of beneficial bacteria – a humid environment and constant contact with air. Irrigated filters are bulky and highly specialized, therefore they are hardly suitable for an amateur aquarium.
External filter canister
Provide all three types of filtration and excellent water circulation, are virtually silent. They have many modifications both for small (up to 50 l.), And for very large aquariums (more than 1000 l.). Productivity does not depend on water level, they work effectively in partially filled tanks, paludarium. Additional options, such as oxygen saturation, ultraviolet disinfection, water heating and more, may be added to the structure. Filter canister is able to combine in itself almost all the necessary equipment of the aquarium, with the exception of the lighting system. Everything rests on the price – it is quite an expensive type of filter, but the most efficient and productive.
Filter material is supplied by manufacturers in various shapes and sizes, so the most important parameter is the substance of which one or another filter material consists. It is the composition of the material determines its scope. Below are the most popular filter materials.
- Calcium carbonate. Used in the form of coral sand, coral chips (crushed corals) or crushed limestone as a chemical that increases water hardness and increases or buffers the pH. It can also act as a mechanical and biological filter. This filtering agent should be rinsed with water before use and thus cleaned of dust. It can be periodically washed and reused.
- Activated carbon. It is used as a means of removing some medicines from water (especially organic dyes such as methylene blue) and dissolved heavy metals. Contrary to popular belief, it does not remove the products of the nitrogen cycle – ammonia, nitrites and nitrates. It can also act as a filtering material for mechanical and biological cleaning. Coal works by adsorption – pollutants are collected on its surface. The amount of substance that it can adsorb is limited, so it needs to be replaced regularly. Coal should be washed in water to remove dust before use.
- Ceramics. Many ceramic products, especially hollow tubes, can serve as filtering material for coarse filtration. They act as a mechanical and biological filter medium and are commonly used in the first section of multisectional filters, since they are not so easily clogged and freely allow the flow of water. They can be washed and reused.
- Synthetic threads. Nowadays nylon yarn is often considered an old-fashioned tool, but it is still an inexpensive and very effective filtering material that allows mechanical and biological filtration. It can be repeatedly washed and reused.
- Sponge. Another cheap and very effective mechanical and biological filter material. Usually sold in the form of cartridges attached to certain filters. The sponge can be washed and reused many times, but in the end it loses its elasticity and needs to be replaced. It is very important to use only a special filter sponge – its other types may be toxic to fish.
- Gravel. Aquarium gravel of any type (but not sand that is too easily clogged), should be washed before use, can be used for mechanical and biological filtration. It can also act as a chemically active filtering medium, unless it is special gravel that is inert to water and does not increase water hardness. It can be washed and reused indefinitely.
- Peat. Usually used as a chemical medium to lower the pH. It can also act mechanically and biologically. It gives water the color of tea (seemingly quite natural to many fish, originating from reservoirs with acidic water). Peat should be used only in a nylon bag (a nylon stocking is ideal for this), since otherwise it will most likely penetrate the aquarium water. Before using the bag with peat should be rinsed in water to wash off the dust.
- Sintered glass. This is a glass that has undergone a special treatment, as a result of which it becomes extremely porous. This results in a very large surface area on which colonies of bacteria settle. Thus a very effective biological environment is obtained. If you use it for mechanical filtering, it quickly becomes clogged. Therefore, even before the water reaches the glass, it must pass, for example, through a layer of sponge to remove from it the bulk of the mechanical suspension. Sintered glass is an expensive material, but because of its high biological efficiency, its relatively small amount is equivalent to a much larger number of filaments, sponges, gravel, etc.
- Zeolite It is a naturally occurring ion exchange resin that neutralizes ammonia and is used primarily as a chemical filter material. It can also act mechanically and biologically. Zeolite has a limited service life, but it can be restored by soaking for 24 hours in strong brine. Rinse with fresh water before reuse. Zeolite should not be used as a daily biological filter filler – otherwise, when it is fully developed, an ammonia crisis will occur in the aquarium. It helps to deal with temporary problems associated with ammonia – for example, in “hospital” aquariums, where medicine is used that is harmful to biological filters, as well as in containers for transporting fish, so that the fish will not be poisoned by their own waste during long trips.
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