Best UV Sterilizers for Reef & Freshwater Tanks (Reviewed 2021)

Updated on January 15, 2021 by

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It is beyond doubt that a clean aquarium environment facilitates a healthy and prosperous living without unpleasant situations and diseases. This applies without exception to any aquatic environment regardless if fresh or saltwater.

A dirty and unchecked aquarium tank will result in a build-up of disease-causing microorganisms that might result in certain diseases or even worse, potential fish losses.

If you’re on the lookout for different powerful filtration options, have a look at our best canister filters, or best HOB filters articles.

Best UV Sterilizers to Use For Your Fish Tanks

Best UV Sterilizer
Emperor Aquatics Smart UV Sterilizer
Emperor Aquatics Smart UV Sterilizer

Tanks: Up to 125 Gallons
Ponds: Up to 2360 Gallons
Size: 3 inch body
Plumbing: 1.5″ Unions inlet/outlet
Suitable: Freshwater & Saltwater
Type: Inline
UV Lamp: 25 Watt

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Runner Up
Aqua Ultraviolet Inline UV Sterilizer
Aqua Ultraviolet Inline UV Sterilizer

Size: 1 x 1 x 1 inch body
Suitable: Freshwater & Saltwater
Type: Inline 3/4″ Barb
UV Lamp: 15 Watt

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Top HOB UV Sterilizer
Aqua Advantage 2000 HOB UV Sterilizer
Aqua Advantage 2000 HOB UV Sterilizer

For Freshwater:
5-200 Gallons
Flowrate: 642 GPH

For Saltwater:
5-70 Gallons
Flowrate: 214 GPH

Size: 18″ X 4″ X 2.5″
UV Lamp: 8 Watt

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Pond UV Sterilizer
Jebao Aquarium UV Light Sterilizer
Jebao Aquarium UV Light Sterilizer

Size: 20″ x 13″ x 4″
Suitable: Freshwater & Saltwater
Type: External
UV Lamp: 36 Watt
Flow Rate: 4400 GPH Max

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Budget UV Sterilizer
Coralife Turbo Twist UV Sterilizer
Coralife Turbo Twist UV Sterilizer

9W: up to 125 Gall

18W: up to 250 Gall
36W: up to 500 Gall
9W: 100-200 GPH

18W: 200-400 GPH
36W: 400-1200 GPH

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Internal UV Sterilizer
Aquatop Submersible UV Filter
Aquatop Submersible UV Filter

Tanks: Up to 100 Gallons
Size: 2.5″ x 12″ x 3″

Suitable: Freshwater & Saltwater
Type: Submersible
UV Lamp: 9 Watt
Flow Rate: 264 GPH Max

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Power UV Sterilizers
Lifegard Aquatics UV Sterilizer
Lifegard Aquatics UV Sterilizer

Inlet: 1 1/4″ Slip or 3/4″ FPT
Outlet: 1 1/4″ Slip or 3/4″ FPT
Size: 7.5″W x 3″L x 21″H
Flow Rate: Up to 450 GPH
UV Wattage: 15W

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25 Watt UV Sterilizer
Aqua Ultraviolet UV Sterilizer
Aqua Ultraviolet UV Sterilizer

For Freshwater:
500-1200 Gallons
Flowrate: 1200 GPH
For Saltwater:
15-150 Gallons
Flowrate: 400 GPH
Size: 20″ x 3.75″ x 6″
UV Lamp: 25 Watt

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What are UV Sterilizers, and how do They Work?

Having the best aquarium filtration system would certainly provide your fish with a healthy environment to thrive and live. However, most filter systems are not designed to eliminate all microalgae and pathogens.

This happens because some of the microscopic organisms are too small to be trapped by the regular mechanical filter system. But when exposed to ultraviolet light emissions, most of these microorganisms are killed or sterilized, making them unable to reproduce.

For this reason, adding the best UV sterilizer to your filtration will ensure that your tank is always clean and safe for your fish and other aquatic inhabitants.

The UV sterilizer for a fish tank is an ultra power filtration system that uses a germicide fluorescent bulb that emits UV light at a wavelength that irritates and eliminates microscopic organisms found in the water column.

This is because ultraviolet light can scramble the DNA of bacteria and other microorganisms, thereby killing or sterilizing them. Being a unicellular organism and having a thin membrane, most microorganisms’ skin can be easily penetrated by the UV light.

Since most bacteria and other microorganisms have a low lifespan in water, sterilizing them would reduce their reproduction and build-up in the tank. This is a better alternative than chemical treatment. No matter how efficient chemical treatments might be, they can also affect the aquatic species.

Simultaneously, the UV light cannot penetrate the multicellular aquatic species like since they have thicker skin. As such, having the best UV sterilizer would ensure that the build-up of disease-causing microorganisms is significantly reduced or even eliminated.

What about Beneficial Bacteria?

Unfortunately, the UV sterilizer does not discriminate between beneficial microorganisms and disease-causing microorganisms. Therefore we recommend not to use the UV sterilizer when the tank is first cycled.

This will allow the beneficial microorganisms to settle and attach to the fish, coral, substrate and filtration media to be relatively safe from the UV emissions later on.

However, UV sterilizers can only kill free-floating microorganisms. They cannot kill microorganisms that are attached to the fish, coral or substrate. As much as this is important for the beneficial bacteria, it is convenient for the disease-causing bacteria.

Where to Install an Aquarium UV Sterilizer?

Because high water turbidity affects the UV sterilizer’s efficiency, we recommend you to install it after the mechanical and/or chemical filter system. This will ensure that the water is cleared before hitting the UV light.

It is also essential to reduce the filter’s water flow rate to allow for a longer contact time with the UV sterilizer. This is crucial to provide effective sterilization of the tank’s water column.

What to Consider When Choosing your UV Sterilizer

When choosing your UV sterilizer, many factors should be considered. This includes, but not limited to tank size, type and size of organisms, contact time, water flow rates, bulb power, UV transmittance, among many others. Let’s tackle the most important ones below:

Tank Size

Because different UV sterilizers come with specific features to work effectively in accordance with the tank size, it is therefore vital to make sure that your tank size matches perfectly with the sterilizer.

Type and Size or Organisms

Different organisms have different resistance to particular UV exposure. Some microorganisms require more exposure to the radiation and UV dosage to be effectively sterilized.

Contact Time

The amount of time a microorganism is exposed to UV light is essential to the sterilization efficiency. The longer the water contact time, the more efficient the sterilization effect will be.

This can be increased by reducing the filter’s water flow rate or going for a UV sterilizer that is designed to reduce the flow of water in the sleeve quartz.

Water Flow Rate

As said earlier, the water flow rate affects the water’s contact time and sterilization efficiency. You should best consider going for a UV sterilizer with an adjustable flow rate.

Bulb Power

The amount of UV emissions is much dependent on the bulb power. This is a measure of the bulb wattage. However, a high wattage also implies that the bulb’s efficiency will decrease in time. As such, the bulbs might need to be replaced more often.

UV Transmittance

This measures how efficiently the UV light gets transmitted and how it penetrates the water. Transmittance can be most affected by water turbidity and cloudiness. However, most aquarium UV sterilizers can thrive in certain degrees of water turbidity.

But this is effectively handled by placing the UV sterilizer after the filtration media.

This article reviews the best UV sterilizers to help you achieve a thriving aquatic environment and have the best fish keeping experience.

1. Emperor Aquatics – Best Aquarium UV Sterilizer

Emperor Aquatics - Best Aquarium UV Sterilizer

When asking for a high-performance UV sterilizer, you should definitely hold on for a bit and take a look at the Emperor UV sterilizer.

With over 30 models to choose from the Emperor aquatic manufacturer provides top-notch aquarium UV sterilizers to suit your preference and application.

The Emperor UV sterilizer is a waterproof and safe unit suitable for freshwater and saltwater ponds and aquariums.

It operates effectively for aquariums up to 125 gallons and for ponds up to 2360 gallons. We can definitely mark it as one of the best built and sturdy aquarium UV sterilizers. It has high durability and longevity because it is made of a thick, corrosion-resistant and UV resistant plastic.

This fish tank UV sterilizer has a 1.5 inches inlet and outlet unions in terms of size, and the body is about 3 inches thick. This device is easy to install and use, simply plug and play out of the box.

It has an easy-to-remove UV lamp and quartz assembly, making it possible to remove the light without disturbing the water flow.

The entire unit can also be easily disassembled for cleaning and maintaining the UV sterilizer.

The quartz sleeves and lamp have an outstanding rating of 9,000 hours (375 days), making it one of the most long-lasting UV lamps in the market.

If you haven’t decided yet, then you’ll be amazed to see this unit also comes with a UV vessel lifetime limited warranty. Sadly, this aquarium UV sterilizer comes with a non-friendly price tag. But this is duly compensated with its high efficiency.

  • High durability and longevity
  • Suitable for freshwater and saltwater
  • Long-lasting UV lamps
  • UV lifetime limited warranty
  • Easy to install and disassemble
  • Does not include mounting brackets
  • Expensive

2. Aqua Ultraviolet – Top Inline UV Sterilizer

AquaUltraviolet - Top Fish Tank UV Sterilizer

This is a product of the “Advantage” series, and it’s a top-notch UV sterilizer for small ponds, aquarium and water environments.

This aquarium UV sterilizer works flawlessly with both saltwater and freshwater aquariums.

As with most “Advantage” series products, it has a sleek design, and it’s a lightweight unit that efficiently provides water sterilization.

It has a high-quality Aqua Ultraviolet UV that can clear your water in a few days and provide your fish with a safe environment. The super 15 watts UV lamp can effectively eliminate bacteria, viruses and protozoa.

The high-quality hard-quartz sleeve allows for a high UV light transmission rate of up to 99%, and it comes with a three-quarter inches barb for easy installation.

An instruction manual is included in the package, which clearly outlines the direction of use. For optimal results, this aquarium UV sterilizer should be operated according to its instructions manual.

  • Hard quartz sleeve
  • Sleek design
  • Lightweight unit for optimal performance
  • Optimal result in a few days
  • Included instructions manual
  • Does not come with a hose clamp
  • Does not come with a mounting bracket

3. Aqua Advantage – Best HOB UV Sterilizer

Aqua Advantage - Best HOB UV Sterilizer

This is an excellent aquarium UV sterilizer for both freshwater and saltwater setups.

It is built with a sleek and lightweight unit that is effective at sterilizing the tank.

It is a super 8-watt powered UV sterilizer that can eliminate green water and provide a clean and safe freshwater environment.

It’s an excellent HOB UV sterilizer for freshwater tanks up to 200 gallons and suitably operated with a max flow rate of 642 GPH. If used in a saltwater tank, it’s recommended for tanks up to 70 gallons and suitably operated with a max flow rate of 214 GPH.

This fish tank UV sterilizer is built with a high-quality hard-quartz sleeve that allows for up to 99% transmission rate, and its UV lamp can last up to 14 months in active use.

When installing it, the half-inch barb fitting will be of great use and help, so you can set up and have the aquarium ultraviolet sterilizer operating in no time. This UV sterilizer reduces excessive plumbing connections as it comes with a hanger spout that hangs on the back of an aquarium or filter box.

Rest assured as this UV sterilizer comes with a limited lifetime warranty on housing against UV degradation and a one-year manufacturer warranty.

There is an included product manual and documentation on optimally installing and using one of the best aquarium UV sterilizers currently available on the market.

  • Optimal clarifier function
  • Suitable for both saltwater and freshwater
  • One year warranty
  • Long-lasting UV lamp
  • Easy to install and use
  • Included user manual
  • Quite pricey

4. Jebao 36W – Best UV Sterilizer for Ponds

Jebao 36W - Best UV Sterilizer for Ponds

Jebao UV sterilizer for fish tanks is another top aquarium device with an attractive price tag that’s hardly rivalled by competitors.

The UV light for aquarium is made with high-quality magnetic ballast suitable for both freshwater and saltwater applications.

It offers a permanent rid of algae blooms and other unicellular organisms to provide a clean and safe tank.

The ultraviolet lamp emits germicidal radiation that alters the genetic coding of the microorganisms such as bacteria, algae and protozoa. A 22 ft cord and sealed transformer powers the aquarium UV sterilizer to provide a maximum flow rate at 4400 GPH.

This UV sterilizer for fish tanks is a non-submersible one, which makes it suitable for external use only. For ease of use, this aquarium UV sterilizer can be installed horizontally or vertically.

From our reviews, we advise you to install it after the filter system to ensure that the water going through the UV light for fish tank, is free from clogs and debris. The ultraviolet quartz sleeve should be cleaned regularly with a swimming pool muriatic acid or lime to ensure that the surface is free of films that inhibit its performance.

For optimal performance, the ultraviolet bulb should be replaced every 6-12 months of usage.

  • Easy installation and usage
  • Efficient at eliminating algae gloomy and green water
  • Excellent result in few days
  • Extra-long power cord and transformer
  • Fairly cheap
  • Product packaging might be faulty

5. Coralife Turbo – Budget Pick UV Sterilizer

Coralife Turbo - Budget UV Sterilizer

If you’re on a low budget and getting yourself worked up on how to get a top UV sterilizer, you might want to check out the Coralife Turbo.

Offering an excellent UV sterilization at a reasonably low price, Coralife Turbo is a perfect tool for your saltwater or freshwater aquarium tank.

It is available in 3 different models, depending on the tank size and its bio-load.

  • Increased exposure due to twist design
  • Operating LED indicator
  • Can handle up to 250 gallons
  • Can be hung-on or inline
  • Easy to install and use
  • Fairly cheap
  • Device operation might be slow

6. Aquatop – Best Submersible UV Sterilizer

Aquatop Aquatic - Best Submersible UV Filter Black

If you’re in the market for an effective UV filter to give you optimal results in no time, then the Aquatop UV sterilizer is a great device to start with.

This UV aquarium sterilizer is suitable and works like a charm for both freshwater and saltwater tanks.

Built to efficiently eliminate microorganisms in large aquarium tanks up to 100 gallons, making it an ideal UV sterilizer for Cichlid tanks.

It is equipped with a super 9 watt UV sterilizer and provides a max flow rate of 264 GPH. The Aquatop UV filter practically eliminates all harmful microorganisms and prevents algae build-up. It also controls the free-floating parasites and disease-causing pathogens, so the fish won’t be in any harm’s way.

Top of it all, this UV sterilizer can serve both as a filter and sterilizer. It is equipped and ready to provide both mechanical and chemical filtration.

The fish tank UV sterilizer has a “hang on back” filter style and a built-in self-adjusting surface skimmer to promote clean water and encourage gas exchange. If your tank is overcrowded and ammonia spikes may occur, this UV sterilizer has a replaceable filter pad made of high quality activated carbon that efficiently eliminates toxic ammonia.

It comes with a large prefilter sponge for mechanical filtration, ensuring the water that meets the UV bulb is free of any food or fish waste.

In terms of installation, this is a submersible UV sterilizer, meaning you don’t have to worry about any plumbing and cumbersome components outside the tank. It can fit on aquarium rims up to 3.75 inches.

  • Easy to install and use
  • Eliminates toxic ammonia
  • Serves as a filter and sterilizer
  • Suitable for both freshwater and saltwater
  • Adjustable flow rate
  • Quite large and bulky

7. Lifegard Aquatics – Fast & Efficient UV Sterilizer

Lifegard Aquatics - Fast Action UV Sterilizer

The Lifegard Aquatics UV Sterilizer is, by all means, one of the best high-quality UV sterilizers that’ll do an excellent job for a long time.

It’s absolutely suitable as a freshwater or saltwater UV sterilizer.

The included quick startup guide, will significantly help you during installation and use as it’s already pre-assembled out of the box.

The Lifegard Aquatics UV sterilizer comes with a sleek design, and you can easily hide it inside the tank behind plants or decorations. Therefore, you won’t have to deal with any tubing outside the tank.

Should you have to replace the UV bulb, there’s a useful LED replacement signal that’ll tell you when it’s the time for that. The fish tank UV sterilizer operates at a maximum water flow rate of 50 GPH. However, the flow rate is reduced with the bulb’s zigzag design to allow for more contact time and optimal operation.

The bulb’s life can be significantly extended, using the aquarium UV sterilizer timer once the water has been cleared. It is powered by a child-safe low voltage of 12V. This aquarium UV sterilizer comes with an impressive 3-year warranty on the pump.

  • Easy installation with no tools
  • 3 years warranty on the pump
  • LED replacement signal
  • Included quick startup guide
  • Totally submersible UV sterilizer
  • Improved sterilization
  • Not very sturdy build materials

8. Aqua Ultraviolet – Best 25 Watt UV Sterilizer

Aqua Ultraviolet - Best 25-watt UV Sterilizer for Aquarium

The Aqua UV Sterilizer is a 25-watt twist UV light for fish tank, that can be installed both inline or submersible.

As a freshwater aquarium UV sterilizer, it can easily handle all sorts of tank setups of about 1200 gallons maximum.

If you plan to use it as a saltwater UV sterilizer, you shouldn’t use it in tanks larger than 150 gallons.

With improved functions, this UV sterilizer for aquarium eliminates microorganisms and helps to reduce biological growth. It has a 2-inch inlet and outlet tubing for efficient water flow. It is a powerful inline aquarium UV sterilizer, that’s one of the easiest to install.

It comes with straightforward installation and operation instructions. The ultraviolet sterilizer for aquarium comes with a long-lasting lamp life of about 14 months, that’s also equipped with a complete lamp quartz sleeve and a transformer.

You’ll be thrilled to see how in just a few days or a week, this UV sterilizer will leave your tank clear and safe from any disease-causing microorganisms. This aquarium UV sterilizer comes with one year warranty from the day of purchase or 18 months from manufacturing date.

It also has a limited lifetime warranty on the housing against ultraviolet degradation.

  • Long-lasting lamp life
  • Comes with complete lamp quartz and transformer
  • One year warranty on purchase
  • Improved sterilization function
  • Included instruction manual
  • Some products were shipped faulty

Conclusion – What’s the Best Aquarium UV Sterilizer?

Having a clean and safe tank for your aquatic inhabitants might be difficult without the help of one of the best aquarium UV sterilizers.

Most microorganisms often cause diseases to aquatic plants and animals, and algae build-up might affect water chemistry. Using chemical treatments to eliminate these bugs can actually cause more harm than help.

Therefore, using the best aquarium UV sterilizer will achieve this without endangering the aquatic species. This makes the UV sterilizer a must-have for every aquarium setup.

From the carefully selected reviews on high quality and affordable aquarium UV sterilizers, you can make a pick easily to suit your application.

The Emperor UV Sterilizer is the overall best aquarium UV sterilizer on our reviews. Sadly, it comes with a not so friendly price tag. But as we all know that top quality has its price, this can be a determining factor when making a choice.

However, if you are on a tight budget and need a UV sterilizer to offer outstanding performance at a fair price, then you might consider checking out the Aquatop UV Sterilizer. The best part about this unit is that it can serve both as a filter and a sterilizer. That is so much to ask for a fair price.