Best Aquarium UV Sterilizer Reviews – Top 5 Picks with Guide, FAQs & More

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You’ll agree with us when we say that UV sterilizers are one of the most underrated pieces of equipment when it comes to aquariums and fishkeeping. 

That’s why we decided to test out and explore many aquarium UV sterilizers in order to truly showcase what they can do. 

In today’s article, we will look at the benefits of having a UV sterilizer in your aquarium and discuss what makes a certain UV sterilizer worthy of your hard-earned dollars.

Top Pick

This product comes with everything you need to easily set it up. It’s incredibly energy-efficient and you’ll be amazed at how quickly it’s able to make your aquarium crystal clear.

Runner Up

Suitable for both saltwater and freshwater aquariums, this product is incredibly versatile. Its high-powered UV bulb is able to clear larger aquariums without breaking a sweat.

Also Great

This product works wonderfully to remove algae, cloudiness and many types of bacteria from your tank. It can simply be clipped to any filter and it’s also very easy to maintain.

After lots of testing under several different conditions, we’ve concluded that these three are the most effective, by far. 

Now, let’s get into the detailed reviews for the top 5 best aquarium UV sterilizers. 

Best Aquarium UV Sterilizer - Best 5 Reviews

1. Overall Best Aquarium UV Sterilizer - AA Aquarium Green Killing Machine Internal UV Sterilizer Review

This internal UV sterilizer kit is the gold standard when it comes to UV sterilizers. You’re not going to need any additional tools or gadgets to install it onto your aquarium and it mounts very simply within minutes. It does not need any setting up or modifying either; You can just turn it on and let it work its magic. 

It has an LED indicator that flashes whenever the internal UV bulb needs changing so you don’t have to constantly monitor it manually. 

Most UV sterilizers we tested took about 2-3 days while this product had our water crystal clear within 24 hours. 

Features of AA Aquarium Green Killing Machine Internal UV Sterilizer – Best Aquarium UV Sterilizer

  1. Dimensions: 16 inches by 10 inches by 14 inches
  2. Weight: 1 pound
  3. Appropriate for aquariums up to 50 gallons
  4. Built-in pump
  5. Maximum flow rate of 58 gallons per hour
  • Doesn’t take up too much space inside the tank 
  • Lightweight
  • Easy to install
  • Quicker than most of its competitors
  • Highly effective
  • Not suitable for larger aquariums 

If you’re looking for a reliable and quick-acting UV sterilizer then this product is perfect for you. It’s beginner-friendly, very easy to mount and you’ll find that it works consistently for a very long period of time.

2. Best Saltwater Aquarium UV Sterilizer - Sun 13W UV Sterilizer Review

UV sterilizers are often restricted in their design in that they’re always made to either work with only freshwater or saltwater aquariums. This is where this product stands out as you can use this with either type of aquarium. 

It has a relatively small footprint and your fish will have ample space to swim inside your tank with this UV sterilizer inside. 

You can easily adjust the water flow inside the UV sterilizer using a simple knob.

The built-in pump means that you don’t have to invest in any additional hardware and the pump itself is quite powerful as it’s able to cycle about 132 gallons of water every hour.

Features of Sun 13W UV Sterilizer

  1. Dimensions: 3 inches by 2.5 inches by 13.5 inches
  2. Weight: 2.6 pounds
  3. Appropriate for aquariums between 40 gallons and 75 gallons
  4. Appropriate for both freshwater and saltwater environments
  5. Adjustable water flow
  • Comes with a built-in water pump
  • Incredibly easy installation
  • Easy to maintain 
  • Compact
  • Works with all kinds of aquariums
  • Motor starts to become jittery after a few months

If you’re not sure what UV sterilizer will work properly for the type of aquarium you have then this is the product you’re looking for. It’s very versatile and works effectively with all kinds of aquariums.

3. Best Easy-Setup Aquarium UV Sterilizer - AA Aquarium Clip-on UV Sterilizer Review

This small piece of equipment mounts easily onto your fish tank filter and just like that, it’s ready for use. 

We found this product to be incredibly impactful because we didn’t expect much from it due to its small size. We were quickly proven wrong though as it took no more than a day for this UV sterilizer to start showing its effects. 

Just after 24 hours of setting it up, we could start noticing the cloudiness and murkiness inside our aquarium decreasing. Visibility was improved by a ton and algae was also eliminated. 

Features of AA Aquarium Clip-on UV Sterilizer

  1. Dimensions: 3.4 inches by 1.9 inches by 2 inches
  2. Weight: 4 ounces
  3. Appropriate for aquariums up to 20 gallons
  4. Clip-on mount
  5. LED indicator for UV bulb change
  • Low energy consumption
  • Small in size
  • Easy to mount
  • Easy to handle and maintain
  • Lightweight
  • Some units have a tendency to burn out 
  • Some reviewers say the sterilizer starts making noise a few days after use

If you’re tired of spending a large amount of time setting up your aquarium equipment then this product is ideal for you. It’s small in size but it packs a very big punch as the bacteria inside your aquarium will find out.

4. Best Lightweight Aquarium UV Sterilizer - AquaUltraviolet Advantage 2000+ Inline Aquarium UV Sterilizer Review

When it comes to UV sterilizers for medium-sized aquariums (40 – 75 gallons), these can take up a lot of space inside an aquarium and they are often quite bulky and difficult to move around. This product, however, is not like those UV sterilizers. It’s incredibly effective and cleans aquariums as big as 75 gallons quite easily but it also has a very small footprint and is very lightweight. 

You’ll find that you’ll have no trouble handling or mounting it onto your aquarium. It’s made from incredibly high-quality material and you won’t have to worry about it breaking down or underperforming as time goes on. It provides consistent performance for a very long time.

Features of AquaUltraviolet Advantage 2000+ Inline 3/4″ Barb – 15 Watt Aquarium UV Sterilizer

  1. Wattage: 15 watts
  2. Weight: 1 pound
  3. Appropriate for aquariums up to 75 gallons
  4. Comes with a timer
  5. Works great in coral reef tanks especially
  • Great focus on water clarity
  • Highly effective 
  • Easy to assemble
  • Very lightweight and easy to handle
  • Excellent build quality
  • Very expensive

If you’re tired of handling heavy and bulky aquarium equipment then this is the product for you. It’s incredibly light but it is able to perform some very heavy-duty tasks. 

5. Best Quartz-Based Aquarium UV Sterilizer - AquaTop In-Line UV Sterilizer Review

This sterilizer is perfect for people who don’t want a lot of conspicuous equipment inside their aquarium. This UV sterilizer is incredibly easy to hide inside any aquarium and it has a design that can easily blend in with an aquarium’s environment. 

It’s not very expensive and you’ll find that its performance is just as impressive as any high-end UV sterilizer you may find on the market. 

It comes in three different size fittings and its intuitive design makes it very easy to install as well. 

Features of AquaTop In-Line UV Sterilizer

  1. Dimensions: 12.8 inches by 2 inches by 2 inches
  2. Weight: 1.75 pounds
  3. Appropriate for aquariums up to 
  4. 10-watt UV bulb
  5. Maximum flow rate: 211 gallons per hour
  • Does not take up too much space inside the tank
  • Can be mounted in a variety of positions
  • Easily mountable
  • Requires little maintenance
  • Budget-friendly
  • Does not come with its own pump

If you’re looking for a quartz-based UV sterilizer at an affordable price then this product is definitely for you. It’s very versatile in terms of positioning and as well as aquarium types.

best aquarium uv sterilizer

Buyers’ Guide

Why should I invest in a UV sterilizer for my aquarium? 

Many aquarists are still apprehensive about having a UV sterilizer in their aquarium and feel as if they’re an unnecessary investment but we’re here to tell you that if you do your research and get a well-made, high-quality UV sterilizer for your aquarium, it can do wonders for your fish’s environment.

UV sterilizers are great for eliminating all sorts of viruses, bacteria and parasites that you don’t even know are present inside your aquarium. UV light passes through your aquarium water and renders these harmful organisms unfit to procreate and reproduce inside your aquarium. This not only protects your fish from a number of diseases but also reduces the workload of your fish tank filter. Considering how a UV sterilizer eliminates a lot of bacteria inside your aquarium, this also causes it to inadvertently prevent cloudy water as well. You’ll find that you’ll have to perform water changes and regular cleanings a lot less often once you set up a UV sterilizer for your aquarium. 

How does an aquarium UV sterilizer work? 

A UV sterilizer comes fitted with a UV bulb. Your aquarium’s water is passed through the UV sterilizer so that UV light passes through the water and sterilizes it. As a result of this UV light, many tiny microorganisms such as bacteria, viruses, and parasites are eliminated and rendered unfit to populate your aquarium. 

The UV sterilizer is able to do this because of the effect that UV light has on the cell structure of these tiny microorganisms. When UV light hits them, their cell structure changes and they are then unable to reproduce. 

Due to this, we must stress that you should not use a UV sterilizer during the cycling process in an aquarium as a UV sterilizer does not differentiate between harmful and beneficial bacteria. If you have a UV sterilizer running during the cycling process, your nitrifying bacteria will not be able to grow and populate. 

What are some things to consider when buying an aquarium UV sterilizer? 

It’s crucial that you get a UV sterilizer that’s appropriate for your aquarium as getting one that’s insufficient or too powerful could have dire consequences for the inhabitants of your aquarium. Some aspects you should consider when buying an aquarium UV sterilizer are: 

  • Aquarium Size 

The size of your aquarium is important as if you get a UV sterilizer that’s too small, it won’t be able to adequately sterilize your aquarium and you will have wasted your money. If you get one that’s too powerful for your aquarium, you may end up killing off bacteria that are actually beneficial for your fish’s environment or worse, you may even start causing adverse effects in your fish and/or aquarium plants.

  • Aquarium Type

Many UV sterilizers are only made to work in freshwater aquariums. If you have a coral reef or a saltwater aquarium, you should ensure that the UV sterilizer you’re getting is able to support those conditions and work effectively in them. 

  • Additional Features 

Once you have the basics figured out, you can look for extra features in your UV sterilizers. Be careful as you don’t want to get one that’s packed with unnecessary features that just drive up the price of the product. Also, be careful if you’re getting a UV sterilizer with enhanced sterilization features as you don’t want to make your aquarium completely sterile. Fish and other living beings inside your aquarium need a balanced ecosystem in order to thrive. They need to be exposed to at least some bacteria so that their immune systems can be healthy. 

How do I maintain my aquarium UV sterilizer? 

You can perform regular cleaning and maintenance by disconnecting your UV sterilizer every month or so and removing the quartz sleeve from it and cleaning it using rubbing alcohol. Be careful not to handle the UV bulb directly as soon as you switch the sterilizer off as it can be quite hot. 

How long do aquarium UV sterilizers normally last?

If you get a UV sterilizer from a well-known, reputable brand, it’s guaranteed to last you quite a long time. A high-quality UV sterilizer can give you consistent performance for anywhere between 5 – 10 years. Most UV sterilizers even come with warranties that last up to 3 years. That being said, the UV bulb inside your UV sterilizer is going to need replacement from time to time. Most decent-quality UV bulbs normally last around 6 months before they need to be replaced. 

Frequently Asked Questions (FAQs)

How can I judge how big of a UV sterilizer I need for my aquarium? 

You don’t really need to do any math or calculations when it comes to UV sterilizers as most manufacturers are generous enough to tell you what sized tank a certain UV sterilizer is appropriate for. 

How do I use my aquarium UV sterilizer? 

You don’t really have to do any extra adjustments to your UV sterilizer once it’s effectively mounted onto your aquarium. All it needs is a pump to make the water pass through it. Once you’ve turned it on, the water can pass through it and be sterilized on its own. 

All you really have to do to ensure it’s proper working is to monitor it and clean and maintain it every time the need arises. For example, the bulb might need replacing after some months and sometimes, dirt gets deposited in the crystal sleeve which you’ll have to clean off. This is important because UV light cannot penetrate dirt and your water would not be effectively sterilized if you leave the dirt on there.

Where on my aquarium should I mount my UV sterilizer? 

A UV sterilizer usually comes with a mounting clip that can easily be mounted onto whatever fish tank filter you have so, normally, UV sterilizers are mounted right next to wherever your filter is mounted. 

If you have an external filter then you should mount your UV sterilizer between the filter outlet and your aquarium so your UV sterilizer sterilizes the filtered water that is coming out of your filter before it reaches the aquarium. 

Are aquarium UV sterilizers effective in coral reef tanks? 

Yes. UV sterilizers are very useful if you have a coral reef tank. UV light is very beneficial to corals as it enables photosynthesis to occur at a more rapid rate. UV sterilizers are also very versatile in that they can adapt to many different surroundings so you can tinker with its strength and flow rate until you’ve found the appropriate settings that are just right for your particular coral reef aquarium. 

Can aquarium UV sterilizers deal with algae? 

Yes. Aquarium UV sterilizers are a great way to deal with free-flowing algae inside an aquarium. It’s important to note that it will only kill algae that’s in the water which flows through the UV sterilizer. This means that algae that has been deposited on rocks or on fish inside your aquarium will remain unaffected and you’ll have to deal with that in other ways. 

Can aquarium UV sterilizers kill the beneficial nitrifying bacteria in my fish tank? 

Yes. As we’ve discussed earlier, a UV sterilizer does not differentiate between beneficial and harmful bacteria, it eliminates all of them. Hence, you should be careful about when you set up your UV sterilizer. Your UV sterilizer should be set up right at the end of your aquarium setup process after the nitrogen cycle is complete. Setting up your UV sterilizer before or during the cycling process will prevent nitrifying bacteria from multiplying. 

Can too much UV light be harmful to my fish? 

Yes. Too much UV light can definitely have undesirable consequences on your fish. This is because an excessive amount of UV light will cause your aquarium to be completely sterile. As a result of this, your fish’s immune system won’t be able to develop properly and they will be very prone to all kinds of diseases. 

Should I turn off my aquarium UV sterilizer at night? 

Yes. You should definitely turn off your aquarium UV sterilizer when you go to bed at night. Most aquariums require about 8 to 12 hours of UV sterilization every day and any amount more than that can have undesirable effects. Not to mention, turning off the UV sterilizer at night will save you electricity as well. 

Can an aquarium UV sterilizer kill black beard algae? 

No. A UV sterilizer is unable to kill black beard algae. To eliminate black beard algae, you will have to employ other techniques such as keeping your aquarium in the dark or introducing algae-eating fish into your aquarium. 

How long will UV light take to sterilize my aquarium?

This can vary by a lot depending on a number of factors such as your aquarium size, the strength and flow rate of your UV sterilizer, the fish you have inside your aquarium, etc. Generally, most UV sterilizers take at least 24 – 48 hours to kill all of the free-floating bacteria inside an aquarium. After you start noticing a difference in your aquarium’s water, you should perform a 30 – 50% water change in order to remove all of the dead bacteria, viruses and parasites from your aquarium. Once this is done, you’ll notice that your aquarium is a lot clearer and cleaner.

Final Verdict

Aquarium UV sterilizers are a great piece of equipment that can really solve a whole myriad of problems when they’re appropriately bought for the right fish tank.

After weeks of heated debates, we’ve concluded the AA Aquarium Green Killing Machine Internal UV Sterilizer to be the best of the bunch. It works extremely quickly, it’s very user-friendly and it also does not have a ridiculous price tag. 

This brings us to the conclusion of our post for the best aquarium UV sterilizers. 

Give us feedback and let us know what aquarium UV sterilizer you’re utilizing.

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