UV Sterilizer

A Guide to Choosing the Best UV Sterilizer for Your Aquarium

There are some persistent issues which you might have to face regarding your aquarium – viruses, bacteria, parasites and algae. These harmful microorganisms not only pollute the water, but can also cause deadly diseases in your fish.

The easiest solution is getting the best UV sterilizer for your aquarium. In this way, you can actively destroy these microorganisms before they pose any harm to your fish.

But what makes a UV sterilizer good? What features should you look for? And most importantly, what are the best UV sterilizers for aquariums?

Don’t worry, this guide will help you out.

IMAGE PRODUCTIdeal Tank sizeRating Price
Best OverallAA Aquarium Green Killing Machine Internal UV Sterilizer with Power HeadAA Aquarium UV Sterilizer with Power Head Up to 50 Gallons
Budget optionSunSun JUP-01 9W UV Sterilizer Submersible Filter PumpSunSun JUP-01 9W UV Sterilizer Submersible Filter PumpUp to 75 Gallons
Best for Large TankCoralife Turbo-Twist UV SterilizersCoralife Turbo-Twist UV Sterilizers50 to 500 gallons (depending on the model)
Aqua Ultraviolet 25-watt UV Sterilizer for Aquarium, 2-Inch, WhiteAqua Ultraviolet 25-watt UV Sterilizer1,200 gallons (freshwater)
150 gallons (saltwater)
AA Aquarium Green Killing Machine 3 WattAA Aquarium Green Killing Machine 3 Watt20 gallons
AquaUltraviolet Advantage 2000+ InlineAquaUltraviolet Advantage 2000+ Inline75 gallons (Reef Tank)
Jebao 36W Aquarium Koi Fish Pond UV Light SterilizerJebao 36W Aquarium Koi Fish Pond UV Light SterilizerUp to 8800 Gallons

What is a UV Sterilizer for Fish Tank?

Simply put, a UV sterilizer is a water filtration gadget which uses the power of UV light to disinfect microscopic organisms.

Among the harmful elements  are:

  • Viruses
  • Bacteria
  • Algae
  • Parasites

With a regular filtration system, you can get rid of all the large debris and nitrogen-cycle toxins, and some of the bacteria and microorganisms.

However, a typical system doesn’t make an aquarium fully free of all kinds of microscopic organisms. In fact, most of the time, a huge amount of these harmful organisms dwell in your tank.

What happens then?

If you have sensitive fish and plants, they may fall victim to these harmful viruses and bacteria.  

This is where a UV sterilizer comes into play. These devices emit UV-C light to destroy the cellular construction of viruses and bacteria. 

You can use a UV sterilizer in an aquarium and even in a pond.  

7 Best UV Sterilizers in 2020

AA Aquarium Green Killing Machine Internal UV Sterilizer with Power Head – Overall Best

AA Aquarium Green Killing Machine Internal UV Sterilizer with Power Head

Currently, AA Aquarium is the most popular UV sterilizer on the market. People love their products because of the unique sealed bulb technology which makes the products very safe to use.

Among all products and models from AA Aquarium, the AA Aquarium Green Killing Machine Internal UV Sterilizer is the crown jewel.

For me, the best thing about this product is its consistency and reliability. The UV wavelength, power rating, and flow rate remain constant and don’t vary after a few months.  

It seems that the main focus of the manufacturing team was to ensure safety. Among all the products on the market, this one is loaded with the highest number of safety protocols. 

The 50 gallons/hour flow rate may make a lot of you skeptical about the performance of this product. However, the lower flow rate is good (in most cases). This means that the UV light and water will have more contact time, ensuring better sterilization capabilities.

Considering every factor, this is clearly the best UV sterilizer for fish tanks or even the best UV sterilizer for planted tanks.

Now, let’s talk about the negative side of the product. There can never be a perfect product. I would say the build quality disappointed me a bit as the outer layer seems to be made of cheap plastic.

Notable Features

  • Patented sealed UV bulb feature ensures you will never have to touch the glass
  • Easy tool-free installation process
  • Control box LED indicator indicates bulb lifetime
  • Sponge pre-filter ensures debris doesn’t enter the UV chamber
  • 50 gallons/hour filtration rate
  • 9W power rating


  • Eliminates cloudy water, bacteria, algae
  • Fully submersible
  • Very easy to install
  • Glass contact-less bulb changing feature with LED indicator
  • Large UV-to-water contact time
  • Superior sterilization results


  • Plastic finish makes the build quality mediocre

SunSun JUP-01 9W UV Sterilizer Submersible Filter Pump – Best Budget Option

SunSun JUP-01 9W UV Sterilizer Submersible Filter Pump

Some of you may think that getting a good UV sterilizer can be a costly investment. Well, that isn’t always true.

For example, look at the SunSun JUP-01. Firstly, this product is a value champ. You are paying a lot less for such a high-quality product. You don’t need to sacrifice much with this product.

SunSun JUP-01 is a lot smaller than other similar products on the market. You can simply stick it to the back of your aquarium and it will take care of the rest. The submersible design makes this product even more lucrative.

The flow rate is also quite good. As it is a standalone device, it comes with a mechanical pre-filter which handles debris.

This small “beast” can handle up to 75-gallon tanks.   

So, where is the “but”? What is the negative side of the product?

It seems that the motor isn’t as good as that in premium top tier products. It will wear out soon if you use it for a prolonged period. In addition, the UV sterilizer will suffer greatly if you put it in a large tank.

But overall, it’s a fine product, considering the price tag and its amazing features.

Notable Features

  • Standalone suction style installation procedure
  • Comes with a mechanical pre-filter for catching debris
  • Can be used in freshwater and saltwater tanks, and in ponds
  • 9W power rating
  • 210 gallons/hour flow rate


  • Minimalist design without the hassle of tubes
  • Budget-friendly option
  • Built-in water pump
  • Standalone device
  • Both horizontal and vertical mounting options


  • Average quality motor
  • Can’t handle large tanks

Coralife Turbo-Twist UV Sterilizers – Best for Large Tanks

Coralife Turbo-Twist UV Sterilizers

OK, so the number one and number two UV sterilizers are only suitable for small to medium-sized tanks.

Now let’s talk about a sterilizer which is the king of the large tanks – Coralife Turbo-Twist UV Sterilizers.

As its name suggests, the biggest feature of this sterilizer is the twist-flow design principle. This means that the water has a twisted flow inside of the chamber. This ensures more UV exposure to dirty water. 

This device is capable of dealing with all kinds of harmful elements in your tank – viruses, bacteria, algae, and parasites.

You get more flexibility with this product. You can put it in your tank as a standalone cleaner or attach it to your existing filter. Yes, the special mounting brackets allow both a hang-on or an in-line installation process.

As for tank size, you can even use this in a 500-gallon mammoth-sized tank. There are four models available. Make sure to choose the one which best suits your tank size.

However, the Coralife Turbo-Twist UV Sterilizer lacks one crucial feature. It doesn’t have a built-in pump for sucking in water. This is a major negative issue with the product.

Notable Features


  • Offers more UV light exposure with twist-flow design
  • Hang-on installation feature with mounting brackets
  • LED indicator signals device activities
  • Suitable for both saltwater and freshwater aquariums
  • Four models available
  • 5W to 36W power rating, depending on size
  • 300 to 900 gallons/hour flow rate, depending on the model


  • Doesn’t have a built-in water pump

Aqua Ultraviolet 25-watt UV Sterilizer for Aquarium, 2-Inch, White – The Durability King

Aqua Ultraviolet 25-watt UV Sterilizer for Aquarium, 2-Inch, White

Don’t you just hate it when you buy a product after putting in so much effort and it breaks down within a few months of buying it?

Yes, we all do!

So, let’s talk about a UV sterilizer which is going to be with you for years to come – the Aqua Ultraviolet 25-watt UV Sterilizer.

Firstly, the build quality of this product is impressive. The water inlet and outlets are two inches wide which allows a greater water flow rate.

Some unique features of the Aqua Ultraviolet 25-watt UV sterilizer is its built-in lamp quartz sleeve and transformers. These two built-in features make the product more compact and easier to install.

Then comes the issue of capability. This sterilizer can handle up to 1,200 gallons of freshwater and 150 gallons of saltwater, so if you have a large tank, it might just be the right one for you.

However, the results are quite slow with this sterilizer. You may have to wait up to two weeks to see significant results in your tank.

Notable Features

  • Large 2-inch inlet and outlet units
  • Built-in lamp quartz sleeve and transformers
  • Reduces chlorine level in the tank
  • 25W power rating
  • Suitable for 1,200-gallon freshwater tanks and 150-gallon saltwater tanks


  • Long lamp life lasts up to 14 months
  • Suitable for both indoor and outdoor use
  • Easy to install
  • Instant start-up


  • May take up to 2 weeks to see noticeable results

AA Aquarium Green Killing Machine 3 Watt – Best Small UV sterilizer

AA Aquarium Green Killing Machine 3 Watt

This UV sterilizer is exactly the same as the one in the number one spot but it is designed for smaller aquariums. Actually, it possesses all the same features such as the patented sealed bulb technology.

However, the AA Aquarium Green Killing Machine 3 Watt has one unique feature – its zigzag flow pattern. The water flows in a zigzag pattern so that the UV bulbs have more time to destroy harmful microorganisms.

With this model, the manufacturers have included a 3W bulb rather than a 9W bulb. Because of this, the device is significantly smaller than other similar UV sterilizers. In fact, I would call it the best small UV sterilizer currently on the market.

Not everyone is looking for a sterilizer which is suitable for gigantic tanks, so if you’re looking for a UV sterilizer for a 10-gallon aquarium, this is the best one you can get.

However, there are some issues which many other users have complained about with this sterilizer. Firstly, you may hear a strange noise coming from the device after prolonged use.

Some have said that the bulb is quite mediocre. So, you should consider these factors when making your decision.

Notable Features

  • Patented sealed UV bulb feature ensures touchless bulb changing
  • Easy tool-free installation process
  • Control box LED indicator indicates bulb lifetime
  • Zigzag design flow pattern for higher sterilization time
  • 3W power rating
  • 50 gallons/hour flow rate


  • Small form factor
  • Exceptionally good results
  • Easy to install
  • Quick action time, can clean the entire tank in just 10 hours


  • Can burn out very quickly
  • Some issues with noise
  • Mediocre bulb quality

AquaUltraviolet Advantage 2000+ Inline – Best Algae Fighting UV Sterilizer Aquarium

AquaUltraviolet Advantage 2000+ Inline

The most annoying problem in every fishkeeper’s life is green clouds of algae in an aquarium. AquaUltraviolet Advantage 2000+ is the best UV sterilizer to fight against green water and cloudiness.

It almost reduces the algae issue to zero. So, if you are not concerned about viruses and parasites but are more bothered about green water, the AquaUltraviolet Advantage 2000+ is probably the best option for you.

It’s an external device which uses the in-line installation feature. Therefore, it’s a non-submersible choice.

You can even use it in your small koi pond, but I wouldn’t recommend doing so. According to the manufacturers, it can handle up to 75-gallon reef tanks. That’s why using it in a pond isn’t a good option.

Notable Features

  • Zero algae and water cloudiness issues
  • In-line installation feature
  • Ideal for small ponds and aquariums and can handle up to 75-gallon reef tanks
  • 15W power rating
  • 233 gallons/hour flow rate


  • Sleek design aesthetics
  • Superior performance
  • Suitable for large tanks and small ponds
  • Easy to install
  • Timer feature


  • Some users have complained about the sealing condition
  • Non-submersible

Jebao 36W Aquarium Koi Fish Pond UV Light Sterilizer – Best for Ponds

Jebao 36W Aquarium Koi Fish Pond UV Light Sterilizer

Fishkeepers with koi ponds suffer the most with green water. Some ponds turn so green that it becomes quite impossible to these your fish.

Let me then talk about the best pond filter (in my opinion) – Jebao 36W Aquarium Koi Fish Pond UV Light Sterilizer.

Firstly, it can eliminate algae blooming altogether in your koi pond. As a result, you will have a completely green water-free pond.

The power rating of this sterilizer is high, and it is rated at 36W, but the best thing about the specs of the device is the flow rate. You will get a staggering 4,400 gallons per hour flow rate with this UV sterilizer.

As you can imagine, such a device is not a submersible one. The in-line installation process is more practical with a device of this caliber.

However, some users have complained about the clips being flimsy, so you should check this device before making a purchase.

Notable Features

  • Permanent algae-blooming elimination, reduces green water to zero
  • In-line installation for external use only
  • Suitable for koi ponds
  • 36W power rating
  • Massive 4,400 gallons/hour water flow rate
  • Can handle up to 8,800-gallon koi ponds


  • Long 22-foot power cord
  • Both horizontal and vertical mounting feature
  • Fast action feature
  • Designed for ponds to fight off algae
  • Superior action


  • The light clips are slightly flimsy
  • Non-submersible

The Benefits of UV Sterilizers in Aquariums: Why (and When) Should You Buy One?

A lot of people ask – are aquarium UV filters worth it? This is because a lot of people already have existing filtration systems in their tanks.  

You don’t need a long list of pros and cons to decide whether you need a UV sterilizer or not.

As you already know, a UV sterilizer mainly works as a tool for eliminating disease by creating microorganisms. So, if you see your fish suffering from any virus or bacteria-borne disease on a regular basis, you should get a sterilizer.

In many cases, particularly due to the mismanagement of your aquarium, water can become badly polluted. You may experience a foul smell coming from your aquarium or see visible cloudiness of the water.

These are clear signs of an abundance of harmful microorganisms in your tank.

A UV sterilizer can help you get rid of these issues. So essentially, it means that a UV sterilizer actually helps you with your tank maintenance duties.

In other words, you will need to change the water in the tank less frequently.

You should definitely use a UV sterilizer in a heavily-stocked tank where you have an abundance of plants or fast-growing plants and a high fish population.

Also, if you have a reef tank with live coral, you should consider getting a UV sterilizer. This is because coral often invites different kinds of harmful bacteria and viruses. Furthermore, you can’t easily clean coral in the tank either. 

Personally, I feel that the biggest benefit of a UV sterilizer is its potential to fight off outbreaks of algae. Among all the nuisances I have to deal with in my aquarium, I hate algae the most.

But from the first day I started using a sterilizer, I have seen drastic results.

However, you should also consider the opposite side of the coin!

Just as it kills harmful bacteria, the UV light will also kill beneficial bacteria. So, those of you who are planning on creating a healthy and natural ecosystem must think twice.

This is especially important when you are cycling the water of your freshwater aquarium for the first time. You need bacteria to nest on bio-media on the gravel.

Make sure to turn off the UV sterilizer during this phase.

In addition, the UV light can alter the nature of helpful medication and supplements.

For example, the chelated copper will convert to ionic copper. A lot of fishkeepers use chelated copper to treat the disease called “ich.” However, the unstable ionic copper is dangerous as it binds with other molecules in the tank’s water. 

So, you should carefully consider the pros and cons. You should get a sterilizer if you have no other options available for fighting off viruses, bacteria, and parasites.

How do You Choose a UV Sterilizer?

What makes one UV sterilizer better than another one? Which parameters should you value the most?

Before you think of those points, you must first learn about the classification of UV sterilizers. There are three types (main) of sterilizers on the market:

  • Tray type
  • Quartz-lined tube type (dry bulb)
  • Non-quartz-lined tube type (wet bulb)

There are also other types of bulbs that many brands offer. Make sure to check which type of sterilizer is most suitable for your aquarium.

Then you should check the power consumption (watt count) and installation process. The watt count varies, depending on size and filtration rate.  

Personally, I prefer the hanging type of sterilizers as they are very easy to use and are hassle-free. 

Also, make sure to get a model which comes with a fully-submersible in-line unit. If the model has water resistance certification rating such as IP-67 or IP68 ratings, it’s even better.

The submersible units are way safer than any other type, and you will get a sense of relief when you have one in your tank.

So, in short, you should consider the following factors before making a decision:

  • Size
  • Flow rate
  • Classification
  • Installation style
  • Water resistance rating

How Does a UV Sterilizer Work?

It gives an assurance of safety when you hear that a device will kill off almost every kind of harmful virus, bacteria, and parasite. But how does a UV sterilizer do that? What is the modus operandi of such a device?

The sterilization process is carried out specifically by a UV-C light. UV-C is the classification of ultraviolet light which has a wavelength between 200nm and 280nm.

Technically, UV-C is quite dangerous, and it can cause sunburn and different skin cell mutation processes in us humans.

But the same property can be used to destroy harmful viruses and bacteria.

UV light uses Ultraviolet Germicidal Irradiation or UVGI method to do this. When UV-C light passes through bacteria, it destroys the nucleic acids in the cells and damages their DNA. This process stops cells from performing essential cellular functions.

In short, bye-bye bacteria and viruses!

So, how does the process take place in your tank?

The device has a powerhead which sucks the polluted water from the tank (or from the existing mechanical filter). After entering the cleaning chamber, the water passes through the UV-C light. Here, the UVGI process takes place. Finally, clean water is then returned to the tank.

But does it pose any harm to your fish?


The UVGI process doesn’t impact the fish as they can’t enter the cleaning chamber. Therefore, you don’t need to worry about it. However, it can reduce the amount of beneficial bacteria in your tank.

How do You Install a UV Sterilizer?

When it comes to the installation process, you must strictly have adhere to the installation guide.

Some UV sterilizers use fixture-style installation kits while others use suction cups. There is no consistent way.

So, if you follow the installation guide from the manufacturers, you will be good to go.

How do You Use a UV Sterilizer in a Fish Tank?

The best way to perfectly use a UV sterilizer device is by adding it to your aquarium’s existing filtration system.

I am assuming that you already have a filtration system which offers mechanical, biological, and chemical filtration.

You will add a UV sterilizer to the water outlet of your filter and then you will have four stages of cleaning.

Some fishkeepers choose to use a sterilizer without making it an addition to an existing filtration system. This idea is also viable, but debris and solid particles may jam the water pipes.

Therefore, the best strategy (in my opinion) is placing a UV sterilizer after a filter.  

Where Can You Buy a UV Sterilizer?

With the increase of online shops and marketplaces, buying any device is easier than ever. You can either buy the device from trusted online stores (such as Amazon) or directly from a seller.

Currently, every major brand offers you the chance to buy directly from their website.

If you are more of a bricks-and-mortar store lover, you can pay a visit to your local pet store. In a real shop, you can physically check the quality of a product before buying. This is a huge advantage.

However, the options can be very limited in this case.

On the other hand, online shops offer you a plethora of options. Personally, I suggest shopping online, and if you are not satisfied, you can always ask for a refund.


Let’s talk about today’s winners. What is the best UV sterilizer for your aquarium?

First place goes to the AA Aquarium Green Killing Machine Internal UV Sterilizer with Power Head. There is no better UV sterilizer with such superior cleaning and safety features.

Next, SunSun JUP-01 9W UV Sterilizer Submersible Filter Pump takes second places. And finally, Coralife Turbo-Twist UV Sterilizers secures third spot.

If you have any questions regarding UV sterilizers, feel free to add to the comments below.


  • William Rieder

    Hi, my name is William Rieder and I'm a pet and animal blogger. I love reviewing all things pet related, from dogs to cats to horses! I also write about other topics such as personal finance and relationships. I enjoy helping people find the perfect pet for their lifestyle and am always interested in hearing what they have to say about their pets.

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