Table of contents:
- How do UV sterilizers work?
- What factors affect the operation of sterilizers?
- In which systems should UV sterilizers be used, and what are the benefits of using them?
- Are there any restrictions on the use of a UV sterilizer?
- What models of UV sterilizers are available for use?
- How to choose the right size for your UV unit?
- How to install a UV sterilizer?
- How to properly operate a UV unit?
Video: Ultraviolet Sterilizers For Aquariums
Ultraviolet sterilizers are used to control pollution by stopping the spread of microorganisms through the water from one fish (coral or invertebrate) to another. Sterilizers are also used in ponds to control free-floating algae. With proper operation of the device, free-floating microorganisms are destroyed by UV radiation.
Note: microorganisms must be in the water passing through the sterilizer. UV radiation has no residual effect and does not kill organisms that infect fish (eg mature stage ichthyophthyroidism) or stones (eg algae).
How do UV sterilizers work?
Such equipment uses herbicidal fluorescent lamps, which produce a wavelength of light of approximately 254 nanometers. Light, penetrating through the cellular structure, damages DNA, modifying it, thus preventing the growth, development and reproduction of the organism.
What factors affect the operation of sterilizers?
* Note: These are general data only. Individual organisms in this group may require a higher or lower dose to kill them.
|The lethal dose of UV rays
(Microwatt per second per square centimeter)
|Bacteria||15,000 - 30,000|
The size and type of organism. In theory, ultraviolet radiation can kill viruses, bacteria, fungi and protozoa. In practice, large organisms such as protozoa may require a higher dose of radiation. Much also depends on the type of organism: some bacteria are more resistant to radiation than others.
Lamp power. The amount of UV light produced by them directly depends on the power of the lamp itself. The more powerful the lamp, the more ultraviolet it produces. Unfortunately, the ability of lamps to produce UV rays decreases over time, so lamps need to be replaced every 4-6 months. The optimum temperature for generating ultraviolet radiation is from 40 to 43 ° C. In colder environments, the productivity of sterilizers decreases.
Penetrating ability… Ultraviolet rays are capable of penetrating water. However, the higher the density of the water, the lower their penetrating ability. If UV rays are not able to penetrate to depth (through water), then there is little sense from them. Cloudy water will also reduce plant productivity. Ultraviolet sterilizers should be placed after mechanical and biological filters, that is, where the water is most transparent and clean. The salinity factor also takes place: in fresh water, the penetrating ability of UV rays is higher than in salt water. Finally, the cleanliness of the lamp and its envelope is important. If the lamp or the shell is covered with limescale, it will simply block the radiation. The distance from the lamp to the surface of the water also has an effect - ultraviolet radiation penetrates into clean salt water only to a depth of 5 millimeters.
Working hours… The more water is exposed to UV radiation, the more harmful microorganisms are killed. The contact time is also often referred to as the "holding time". The holding time depends on the water flow. The lower the flow rate, the longer the contact time. The length of the lamp also has an effect. With a long lamp, the contact time of water with the sterilizer increases. Another value to consider is the time it takes for the entire volume of water in your aquarium to pass through the sterilizer. Since pure water constantly mixes with the water in the aquarium, it is almost impossible to sterilize all the water. To do this, you would have to remove all the water from the aquarium, sterilize it separately, and then pour it back. In this situation, we sterilized the water, of course, but we would also have to do something with the inhabitants of the aquarium, without water, unfortunately, theydo not live.
Temperature. UV rays are best distributed in water temperatures of 40-43 ° C. The quartz lamps, in turn, will help maintain a higher temperature, thereby ensuring greater productivity of the entire system. Quartz sleeves allow you to isolate the lamp from the cool water in your aquarium and maintain higher UV performance. In theory, UV sterilizers can be used in any aquarium. However, in small aquariums (60 L or less), the cost of the setup can make it impractical to use. These installations are most practical in multi-level aquarium systems. In water bodies, such systems are the best way to combat unwanted algae growth.
In which systems should UV sterilizers be used, and what are the benefits of using them?
Such systems are most effective in multiple systems separated by a common filter. In a conventional system, the sterilizer can be effectively installed to prevent contamination of all fish when signs of disease appear in the aquarium inhabitants. This is especially convenient in densely populated aquariums, with many living rocks, corals, that is, where it will be difficult to catch infected fish. Disease control is also essential when you add new fish to the aquarium, especially since 98% of aquarists do not use a separate aquarium for quarantine. In water bodies, the use of sterilizers is necessary to control free floating algae. This way you can enjoy the view of your pond in peace.
Long-nosed butterfly fish (Chelmon rostratus)
Are there any restrictions on the use of a UV sterilizer?
It should be understood that ultraviolet systems cannot serve as a complete substitute for mechanical and biological filtration. The UV unit is just an addition to your filtration system.
UV sterilizers are useless against algae, worms and other organisms that do not float freely. A UV sterilizer is usually not harmful to the aquarium, but should not be used as a panacea as it can kill the beneficial bacteria found in filters and gravel. Many medicines will be ineffective with the sterilizer, especially those based on copper. UV radiation will release bound copper ions and their concentration can be lethal.
Sterilizers can be used to control parasites, but this will be impractical in larger systems unless more powerful units are used. A UV unit can heat water, especially if it is more powerful than your aquarium requires.
Related article Aquarium lighting: spectrum and intensity
What models of UV sterilizers are available for use?
Sterilizers differ in their position in the aquarium (horizontal or vertical), as well as in how they are located in relation to the flow (suspended or in the flow line). All vertical systems must be vertical and not otherwise, while some models of horizontal sterilizers (eg Rainbow) can also be vertical. Some options can be installed in-line or behind the tank. Specialized models can be used in outriggers.
New models of UV units are called "double helix". They increase the contact time between the water and the installation, due to the fact that the water makes a double turn in a spiral, passing through the installation. Some models may have a quartz sleeve, others come without it. Those models, which have a coupling - I call "dry lamps". These models are essential in cold aquariums to ensure optimal UV production. They are also easier to clean and replace.
It is believed that a good sterilizer should include the following:
- Loose ballast that can be placed in a location that is protected from water and heat.
- Indicator that will show if the installation is working.
- Automatic switching function.
- Connecting elements.
- Quartz or Teflon sleeve.
- Non-corrosive parts that come into contact with water.
- Adequate guarantees and obligations.
Brocade pterygoplicht (Pterygoplichthys gibbiceps)
How to choose the right size for your UV unit?
This is perhaps the only difficulty in handling the UV unit. In order to effectively kill harmful organisms, your UV setting must be matched to the size of your aquarium. Most manufacturers of UV sterilizers provide their product with a special table. By comparing several well-known models, you will realize that tables and measurements may differ for each firm.
|Manufacturer / model||Wattage||Max. Liters||Stream strength|
This table shows the differences between several well-known manufacturers. And as we can see, these indicators are quite different from each other. The power required for Emperor Aquatics is significantly different from other manufacturers. This is due to the fact that they use a coefficient of absorption of water purity of 0.45, and the throughput of the quartz sleeve is reduced by 20%. This reduces UV leakage and improves lamp performance.
How to install a UV sterilizer?
The UV unit must be the last link in the filtration system before the purified water enters the aquarium again. The sterilizer must be installed after biological, mechanical and chemical filtration systems. Follow the manufacturer's recommendations when installing the UV system. Most UV systems are equipped with special spike mounts that easily attach to the aquarium.
Related article Sterilizing an aquarium
How to properly operate a UV unit?
The quartz sleeve must be cleaned once a month by wiping with an alcohol solution. Some large models are equipped with special brushes to make them easier to clean. In most cases, the UV lamp needs to be replaced after 6 months from the date of installation. However, lamp life may vary from manufacturer to manufacturer, so be sure. When replacing or cleaning the lamp, do not look at the switched on device. This can damage your eyes and cause discomfort. Switch off the instrument before servicing to avoid electrical shock. A working lamp in air heats up very much and may burst when immersed in cool water.