A UV sterilizer is a filtration device that removes bacteria, algae, fungus, protozoa, and other single-celled organisms from water. It is safe for your fish and easy to maintain. A UV sterilizer is a great addition to your tank’s filtration system.
When choosing a UV sterilizer, you need the right size and strength for your tank. An undersized or underpowered UV sterilizer will not do enough to clear your water, so make sure you read the specifications and choose the right size for your setup.
How Does a UV Sterilizer Work?
A UV sterilizer consists of two tubes: an inner tube containing the UV light and an outer tube that pumps water. The water that passes around the inner tube is exposed to the UV light emitting from the tube.
When water passes through the light of UV sterilizers, the ultraviolet rays kill single-celled organisms by mutating the organisms’ DNA, making them unable to reproduce. UV light can therefore save your aquarium fish from potentially deadly infectious diseases.
UV sterilizers are safe for fish and safe for the plant life in your tank. The only water affected by the unit is the water that passes directly through the light. The UV light cannot get into the rest of the water or affect the DNA of your fish.
Top 5 Best Aquarium UV Sterilizers
We’ve compared the features of three of the top aquarium UV sterilizers. The expert at your local aquarium store is another excellent resource for information about which UV sterilizer is correct for your tank.
Let’s take a look at a side-by-side comparison of these five models.
| Product | Watts | Capacity (saltwater) | Price |
| Coralife TurboTwist | 18 watts | 250 gallons | $160 |
| Aqua UV Classic | 25 watts | 150 gallons | $575 |
| Aqua UV Advantage | 15 watts | 75 gallons | $189 |
| Fluval Inline | 5 watts | 30 gallons | $85 |
| Coralife BioCube | 5 watts | 30 gallons | $56 |
Let’s look at five of the best UV sterilizers for your aquarium.
Aqua UV Classic
- Fresh Water Sterilizer: 1,500-3,000 gallons; Flowrate - 3,200 gph for 30,000 µw/cm2SUP>
Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API
The Aqua UV Classic is the best USA-made sterilizer available on the market. For those living in the states, it is a good alternative to something like the TMC Vectron because it is easier to find, order, and ship for customers outside the UK.
The unit has an extended dwell time. It is a large unit used in a sump system or even a pond. The Aqua UV Classic can clear water as quickly as overnight or within 3 to 5 days after installation.
The unit can sterilize up to 1200 gallons of freshwater or 150 gallons of saltwater in a marine tank. It is also rated to clear free-floating algae from a freshwater setup of up to 4000 gallons with 50-75% plant coverage.
Pros
- Best sterilization available in a US-made unit
- Long dwell time
- Can handle large tanks
Cons
- Expensive
- It may not work for smaller tanks
Coralife TurboTwist UV Sterilizer
- Removes free floating algae, parasites and harmful micro organisms from aquarium water
Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API
The Coralife TurboTwist UV Sterilizer is considered one of the best UV sterilizers on the market.
The Vectron has a longer dwell time than many other UV sterilizers. This is because of the chamber’s unique twisted design shape that sends water through a helix around the bulb. The twisted shape means the water is exposed to the UV rays for longer. It also has a T8 UV bulb, which is wider than most sterilizers’ standard T5 UV bulb.
The Coralife is a good budget alternative to the quite expensive Aqua UV Classic. The only drawback to the Coralife unit is that it is slightly more expensive than other budget options on this list. It is still cheaper than something like the TMC Vectron, however.
Pros
- The longest dwell time of any UV sterilizer on this list
- Unique twisted UV bulb chamber
- The convenient docking bay makes it easy to install
- Works in larger tanks
Cons
- More expensive than other options
- The sterilization is not as good as the Aqua UV Classic
Aqua UV Advantage
- The Advantage Series is ideal for small ponds, aquariums and water features
Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API
The Aqua UV Advantage sterilizer is a compact unit that hangs on the back of the tank and is intended for smaller aquariums. It is a great value option and the best UV sterilizer for those on a budget.
The Aqua UV Advantage is a level one sterilizer, meaning it will kill most bacteria and viruses and some stubborn parasites. It is not big enough to be classified as a level two sterilizer, but for its size, it offers the best UV sterilization available.
The Aqua UV Advantage hangs on the side of your tank. It cannot be modified to run inline in the filtration system because the hanger is also the return. It is rated to sterilize up to 500 gallons of fresh water or 75 gallons of salt water. It is an ideal solution for a hobbyist or someone with a smaller tank.
Pros
- Small, compact size and easy to install
- Best sterilization available for a unit of its size
- Works with sumpless tanks
Cons
- Short dwell time
- It does not provide level two sterilization
- It will not work for large tanks
Fluval Inline UVC Clarifier
- A chemical-free and maintenance-free way to purify water that eradicates suspended bacteria and algae in the water column that contribute to cloudy and green water, respectively
Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API
The Fluval Inline UVC Clarifier is another excellent option for those on a budget. It is very effective at clarifying green water, as it is rated to remove algae. It is not a very powerful unit and is not intended for sterilization. The Fluval Inline UVC Clarifier is rated for clarification only.
The Fluval Inline Claifier is a good option if you often deal with green and cloudy water. However, if you are dealing with a parasite infestation, bacteria, or virus, consider another unit, as this one cannot handle those issues.
Pros
- Budget-friendly
- Excellent at clarifying water
- Removes excess algae and green water
Cons
- Not intended for sterilization at any level
Coralife BioCube UV Sterilizer Mini
- Aids in eliminating harmful parasites, bacteria and free floating algae
Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API
The Coralife BioCube UV Sterilizer Mini is a small unit intended for small tanks. It is much cheaper than the other options on this list; however, it will not work in a large aquarium. It’s an excellent option for quarantine tanks. It provides sterilization and clarification.
The unit is easy to install without any tools or complicated plumbing procedures. It includes a mechanical filter sponge that will remove large particles and can take the place of a filter sock. It has a similar capacity to the Fluval Inline Sterilizer, but it is rated for sterilization instead of just clarification.
Pros
- Budget-friendly
- Intended for sterilization
- Great for quarantine and other small tanks
Cons
- Not intended to be used in large tanks
What to Consider When Buying a UV Sterilizer
UV sterilizers are a great addition to your aquarium’s filtration system. They can rid the water of many single-celled organisms, including bacteria, viruses, protozoa, fungi, algae, and parasites like ich.
Contrary to popular belief, a UV sterilizer will not harm your tank’s fish and other life. The light can only affect organisms in the water that passes directly through it. Water is pumped through a chamber lit with a UV light, and while the water is in the chamber, the light mutates the DNA of the cells in the water.
The most important things to consider when shopping for a UV sterilizer for your aquarium are the tank size and the UV sterilizer’s flow rate. The next most important features to consider are the wattage of the UV bulb and what types of organisms you hope to eradicate.
The flow rate of your UV sterilizer should be equal to or greater than the number of gallons in your tank and sump. For example, if you have a 150-gallon tank, the sterilizer should have a flow rate of 150 gallons or more.
Different UV light wavelengths work on different microorganisms types. Here is a breakdown of which types of UV light kill which organisms:
- Bacteria: 15K uw seconds/cm2
- Viruses: 15K–30K uw seconds/cm2
- Algae: 22K–30K uw seconds/cm2
- Fungi: 45K uw seconds/cm2
- Protozoa: 90K uw seconds/cm2
So, if you need to clear your water of a particular type of bacteria, you may need a UV light with a lower wavelength than you would need to clear fungi or algae.
Related article: How long to leave your UV lights on in a fish tank
FAQs
Here are some frequently asked questions about UV sterilizers for aquariums.
Should I Run My UV Sterilizer All the Time?
Yes. A UV sterilizer should be on and running 24 hours a day, seven days a week. Unlike the regular light or LED light in your aquarium, which is intended to mimic sunlight and should follow a natural light cycle day and night, the UV sterilizer is a filtration device.
The UV sterilizer can only sterilize the water when it is turned on. The only times you should turn the light off are when you are adding beneficial bacteria to the water or using medication in the water that stipulates that the UV light should be turned off.
How Do I Choose a UV Sterilizer for My Aquarium?
To choose the correct UV sterilizer for your tank, pay attention to the size of your tank and the flow rate of the sterilizer. The maximum flow rate of the sterilizer should be greater than the total gallons in the tank and sump.
For example, if you have a 100-gallon tank, you would need a sterilizer with at least a 100gph (gallons per hour) flow rate. You should also select at least an 18W bulb in this circumstance. Going for a larger flow rate and higher wattage is always preferable. If you have a 100-gallon tank, a 25W bulb and 125 gph flow rate are best.
Are UV Sterilizers Worth It?
A UV sterilizer is certainly an expensive investment, and while it is not necessary, it does make a great addition to your tank. A UV sterilizer can prevent disease outbreaks from viruses and bacteria, which could lead to fish death or even the collapse of your entire ecosystem.
UV sterilizers also help with water clarity by killing algae and fungi that can cloud water. While cloudy water is not necessarily a threat to your tank, it can lead to other problems and decreases your enjoyment of the aquarium.
While a UV sterilizer is not a necessary purchase, it is definitely worth the investment. There are several good options on the market. When shopping for a UV sterilizer, take into consideration the size of your tank and any specific bacteria you need to eliminate.
I hope this goes for Turtle Aquariums too I have a turtle a rescued this is my first time owning an aquarium.
Hi Kathleen,
Yes, aquarium UV sterilizers can be used in turtle aquariums as well. UV sterilizers can help control harmful bacteria and algae in the water, which is important for your turtle’s health. However, it’s important to ensure you use the correct size and type of UV sterilizer for your aquarium, as different models have different capacities and requirements.