Filtering Your Aquarium Water
(The First Tank Guide)
What Is an Ultraviolet Sterilizer?
Ultraviolet sterilizers, or UV sterilizers or just sterilizers, are not filters in the traditional sense, in fact, sterilizers do not provide mechanical, chemical, or biological filtration. Ultraviolet sterilizers are used to kill unwanted microorganisms by exposing them to lethal radiation.
A sterilizer can help reduce chances of disease transmission in aquariums by killing off many of the disease organisms before they have a chance to infect fish or spread from one fish to another. Of course, this can only work for free-floating or free-swimming microorganisms.
How Does an Ultraviolet Sterilizer Work?
UV sterilizers expose passing water to lethal doses of ultraviolet light, killing, sterilizing, or otherwise irreparably damaging many microorganisms (bacteria, fungi, protists, viruses, etc.). Water is pumped slowly through a crystal sleeve past a high intensity ultraviolet light. The sleeves are designed to allow the maximum amount of UV radiation to pass through to the water.
This can have several effects on the microorganisms in the water. It may rupture their cell membranes or cell walls, it may damage their DNA or RNA, or it may damage other organelles in the cells - in short, it puts them out in the sun too long without sunscreen!
Sterilizers can also help control free-floating algae in the same way. However, when an ultraviolet sterilizer kills algae it does nothing to take the algae out of the water, so the water may remain green.
The water must move through the ultraviolet sterilizer slowly so that microorganisms receive maximum exposure to the harmful UV light and are less likely to be able to spread disease to between your fish.
This is all within an opaque tube, canister, or case. The opaque case blocks any UV light from getting out and possibly harming you or your fish or other pets.
What Maintenance Does an Ultraviolet Sterilizer Require?
Ultraviolet sterilizers require three things. First, the pump must be in good order, so you will have to keep your pump clean. Second, the crystal sleeve needs to remain clear and free of debris, so you will have to clean it regularly (every 3-15 months, depending on feeding and cleaning habits, type and population of fish, type of filter used, and material of sleeve). Finally, the bulb will need to be replaced - every 3-12 months depending on water flow rate and type of bulb.
It is important to be aware that the sleeve in an ultraviolet sterilizer may be easily scratched, so you will need to be careful when cleaning it. As it becomes scratched, it will need to be replaced, since a scratched sleeve will make the ultraviolet sterilizer less effective.
What Should I Be Aware of with an Ultraviolet Sterilizer?
While ultraviolet sterilizers can be very helpful in keeping your tank and fish healthy, they are very expensive, and, like most filters, they need to run constantly.
Also, sterilizers kill beneficial and harmful microorganisms indiscriminately - it can't tell one from the other.
Unfortunately, some microorganisms are not sufficiently affected by the exposure to UV radiation, so not everything will be killed; as a pet owner, you will still need to perform your regular maintenance and treat any diseases that come up.
Remember that any microorganisms that your sterilizer kills become part of the waste that your filter then needs to filter out. In some cases, this can have an impact on the efficiency of your biological filtration, but usually the impact is minimal.
Sterilizers do not provide mechanical, chemical, or biological filtration.