Ultraviolet sterilizers are used to destroy microorganisms, bacteria, viruses, as well as various protozoa and algae freely floating in water. In this case, only water that passes through the sterilizer is subject to disinfection, therefore the algae attached to the ground, parasites on fish and everything that is not in free swimming is not subjected to sterilization.
The principle of operation is based on the fact that powerful ultraviolet radiation penetrates into a living cell and kills it, so it is detrimental to all living things, but the doses required to kill viruses, algae and other microorganisms are very different. The UV wavelength in sterilizers is approximately 254 nm.
|Organism||Lethal dose (microwatts per second / cm2)|
The table shows the averaged data.
Although ultraviolet radiation is detrimental to all living things, in practice it helps to destroy only protozoa and viruses in water, and various species with varying success. The lamp power, its length and the emitted light spectrum directly affect the efficiency of the sterilizer as a whole.
An important factor in the quality of the sterilizer is its design. Do not forget that the lamps in these devices should be changed at least 2 times a year, since their radiation power decreases significantly with time.
One of the significant disadvantages of ultraviolet radiation is its low penetrating power. So ultraviolet rays can not pass deep into the water. With increasing salt content in water, the effectiveness of UV rays decreases even more.
Turbid water significantly reduces the effectiveness of the sterilizer, and limescale on the lamps can completely block access to the rays. And, generally speaking, the rays penetrate into pure fresh water no deeper than 5 millimeters.
To achieve the greatest effect, sterilizers are installed only after all water filters, i.e. sterilized should be the most purified from minor impurities and organic water.
Since different organisms in the water require a different lethal dose of ultraviolet radiation, it is necessary to select the power of the sterilizer according to the highest value. This value is set by the duration of the contact time of the water with the UV lamp and the power of the lamp itself.
The slower the flow of water, the longer it comes into contact with the lamp, the more pathogenic bacteria in it die. If the lamp is long – it also increases the time of contact with water.
You should also consider such a parameter as the time during which the sterilizer completely surpasses the volume of water equal to the volume of your aquarium. Naturally, all the water in the aquarium during this time will not pass through the sterilizer, since at the output, it is constantly mixed, but it will be an approximate parameter by which you can determine the performance of a particular sterilizer lamp.
The best ambient temperature for quartz lamps is not lower than 40-43 degrees, since at lower temperatures, the UV flux from the lamp drops significantly. Good and high-quality sterilizers supply quartz couplings that prevent cold water from the aquarium from cooling the lamp, thereby improving its radiating ability.
Ultraviolet sterilizers are beneficial to install in large aquariums, in overcrowded aquariums or with a large number of inhabitants, where you can simply not notice the sick fish, sterilizer will avoid the outbreak of the disease. It is also useful at the time of the new fish sharing in the aquarium.
It is simply necessary in reservoirs, since allows you to control the number of free-floating algae.
As we said earlier – ultraviolet radiation is detrimental to all living things, so you should not get too carried away with the work of the sterilizer, because In addition to any nastiness, beneficial bacteria are removed from your tank that support the biobalance in it. Do not forget that sterilizers do not produce mechanical filtration, so it makes absolutely no sense to use them instead of filters, they should only be used in conjunction with the existing filter system.
When treating fish with drugs, sterilizers are not recommended to be included, since The drug under the action of ultraviolet loses its healing properties. These devices as well heat the water in the aquarium, which can adversely affect the fish in the summer in the heat.
By design and installation method, sterilizers differ in horizontal and vertical, as well as on how they are located relative to the flow (suspended or in the flow line)
For cold aquariums, there are sterilizers with a special quartz coupling (with a dry lamp) that prevents water from coming into contact with the lamp. They are easier to clean and change.
In order to choose an ultraviolet sterilizer for an aquarium, it is not necessary to calculate any complicated formulas, each manufacturer indicates on the package for what volume of water and what type of aquarium a particular sterilizer is intended, so even a novice should deal with this issue.
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