Aquarium UV Sterilisers

Keeping your aquarium clean and the fish happy requires quite a lot of effort. If you do not have a quarantine fish tank for new arrivals and maybe sometimes forget to perform the maintenance tasks, you need extra help. Aquarium UV sterilisers are handy water filtration devices that make your life easier in this respect.

UV Steriliser Basics

The basic working principle of a UV steriliser is simple. A pump draws water inside the steriliser and through a crystal sleeve. The device exposes passing water to lethal doses of ultraviolet light, thus killing or damaging microorganisms like fungi, algae, bacteria and viruses. The slower the water moves through the steriliser, the more radiation the microorganisms experience. The tube in which the steriliser rests is opaque, so no light passes through and cannot harm your fish or other pets.


To achieve the maximum effect, the UV steriliser needs to be at the last position in the filtration line. The aquarium water must first go through the mechanical filter and only then into the steriliser. The mechanical filter removes solid particles, and the steriliser can thus work at its maximum operational efficiency.

Features to Consider

When choosing a steriliser, consider what kind of light bulb to use inside. Generally, the light bulbs vary from 8 watts up to 130 watts. Obviously, the larger your fish tank or the lazier you are, the more efficient the bulb should be. Also note that the effectiveness reduces over time, and you need to replace the bulb after six months of use. If you choose a bulb with lower wattage, you should also pick one with a lower flow rate to maximise the device's efficiency. The flow rate's measurement unit is litres per hour, indicating how much water can pass through the steriliser within 60 minutes. Higher flow rates are best for killing bacteria and algae, while lower flow rates deal better with parasites. If you know what kind of microorganisms you want to deal with, you already have an advantage in the selection process.

Water Types

It does matter what kind of water you use in your fish tank and thus dedicated UV sterilisers are available for different applications. While you could choose a universal aquarium UV steriliser, you would probably be better off with a dedicated saltwater or freshwater device. Moreover, you can even find pond UV sterilisers that can handle the algae growth better as algae is more typical in ponds.