Best UV Sterilizer for Aquarium Fish Tank Reviews for 2018

Sterilization is well-known in the medical and pharmaceutical industries for its effects on health promotion and contamination elimination. Along with increasing demand for fish tanks, the same for sterilizers goes up at the moment. Not like a decoration of the house, but sterilizers are necessary to keep fish tanks or other sources of water clean and crystal clear. 

Which are the best UV sterilizers on the market?

1. Aqua Ultraviolet

Aqua Ultraviolet - Advantage 8-watt UV Sterilizer Inline for Aquarium

Best UV Sterilizer for small aquarium


  • Wattage:  8W   
  • Maximum Capacity: 200 gallons of fresh water or 70 gallons of salt water
  • Voltage: 110v /60hz or - 240v/50hz


  • Designed by versatile technology, this UV sterilizer is good to use in different environments such as disinfecting water, opaque liquids, hard surfaces or even in the air
  • The light is as natural and compelling as sunlight
  • The device contains no chemicals. It deals with water physically only. Hence, water or animal have got no effects from chemistry

For those features and specifications, this UV sterilizer is favorite in many industries such as pharmacies or medical because the device can clean up drinking water without changing the taste or physical features. Or sports, this product is powerful enough to install for ponds or swimming pools.

Aqua Ultraviolet Advantage 8-watt is known for its versatility. It is compatible with disinfecting water, hard surfaces or even in the air. Plus, this UV sterilizer doesn’t release any chemicals.

The drawback of the 8-watt model from Aqua is that it is not a budget-friendly option. However, with all the useful features it offers, I am sure you won’t mind paying extra bucks to get your tank clean and bright.


  • This level 1 UV sterilizer will kill pathogens and protect fish health, while many other types of UV sterilizers on the market can deal with algae only. Using this device in the fish ponds, fish are safer with another sickness, one of the best nano uv sterilizer.
  • This device can even reduce possibilities of leaking
  • To keep it long lasting and convenient, all of the parts can purchase on the market. Something such as seals, tubes, bulbs, can be found and changed quickly. Unless it stopped running, this little thing never becomes waste.


  • High price, however, you can barely get anything excellent and effective in a low cost
  • The instruction of use may be confusing to some users.
  • Small ponds can show up the effectiveness better
  • Because the bulbs are very important and changeable, manufacturers have sold it at high price.

Aqua Ultraviolet - 15 watt Advantage 2000+ Hang On UV Sterilizer

Best UV Sterilizer for hang on


  • Wattage: 15W   
  • Maximum Capacity: 200-500 gallons of fresh water or up to 75 gallons of salt water
  • Voltage: 110v/60hz or 240v/50hz


  • This small and lightweight device is recommended for small ponds, aquariums and water features where people can maximize sterilization.
  • This powerful UV Sterilizer has effects on common bacteria, viruses, and even protozoa
  • With 60-75gallon tank, the device can work fast and perfect in eliminating odor, ammonia level, and harmful bacteria. Such a cure to make your ponds clean and see-through again

Because of a slim and lightweight design, this product is favorited for domestic fish tanks where people need a crystal-clear look all the time. The device works fast in recommended fish ponds ( which are in the house) and keep them always bright and clear out of algae or horrible bacteria.

The 15-watt model is ideal for small fish tanks. It takes up to 19 hours for this UV sterilizer to work, and most users leave positive comments on its efficiency. There are a few shortcomings though. Since it is only compatible for small tanks, those who own larger ones don’t find this item very much useful. What’s more, it’s quite hard to change the bulb.


  • The light and slim look makes it a perfect choice for small find ponds or small aquarium decorations
  • Fast work with only 19 hours to two days keep users a wow after installing the devices in horrible vague and dirty ponds.
  • Protect the environment for fish to live up and greed.


  • The productivity is only limited to small fish ponds and tanks
  • The bulb seems hard to change or replace.
  • The device should be kept on all the time for the best effectiveness

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

Aqua Ultraviolet 25-watt UV Sterilizer for Aquarium

Product description

  • Wattage: 25W   
  • Maximum Capacity: 1200 gallons of fresh water features and 150 gallons of saltwater aquariums
  • Voltage: 110v/60hz or 240v/50hz


  • What you are looking at is a UV sterilizer with double power for much larger fish ponds.
  • No one could have any troubles during installation because the instruction is smooth and clear.
  • The manufacturer of Aqua Ultraviolet leaves users with high technology and the most durable lamp. This bulb can work well up to 14 months. 
  • The Best UV Light Aquarium ever with fast effects after installation (a fish pond with 2500 gal can be cleared in 4 days) and you would never see your ponds in such clear.

The same line of products but this one provide you with a more significant effect in case there’s a larger pond in the house. The product has the best lamp on the market that you could find at the moment. The product is durable if you are good enough at changing the bulb, the only one must be replaced after every two years.

If you are looking for a powerful UV sterilizer, this is the one. Its emits strong and durable ultra-violet light to clean off a large area in relatively quick. It is advised to use this product outdoor with extra protection to prevent damages. This is one of the best uv sterilizer saltwater aquarium on the market.


  • This sterilizer works well for much larger fish pond or pools.
  • It takes more time to deal with a more extensive area, but, with this Aqua Ultraviolet, the time gets shortened
  • It has got the most durable light on the market.
  • The lifecycle is permanent as long as users can do changing bulb frequently every year.
  • The lamp and transformer are included in the package with sterilizers.


  • The transformer must be changed if the bulb gets altered into different productivity
  • The product can be used outdoor but better with protection.

Aqua Ultraviolet - Classic 25 watt UV Sterilizer, 3/4"

Aqua Ultraviolet - Classic 25 watt UV Sterilizer

Product description

  • Wattage: 25W   
  • Maximum Capacity: 1200 gallons of fresh water features and 150 gallons of saltwater aquariums
  • Voltage: 110v/60hz or 240v/50hz


  • The UV sterilizer is made with popular, versatile technology by Aqua Ultra Violet so that people can apply in different surfaces such as disinfecting water, opaque liquids, or the air
  • The product has got outstanding features of a typical Aqua Ultraviolet products: no chemical on processing, no harms to fish in the tank and no causes for fish health problems.
  • The UB light is designed to work the same as UV beam found in sunlight.
  • It shows off the effectiveness through fast working time. The fish ponds can come clean from 3 to 5 days after installation.

This product is the combination of the best in the Aqua Ultraviolet product line. Besides the best features, it looks simple and robust in black. This device is made to deal with larger fish ponds. Users can easily take the beautiful and bright look of the pond in some days of using. 

Aqua UV Classic 25 watt is one of the fastest working UV sterilizers in the list. It only takes this product up to 5 days to clean off a big fish tank. It doesn’t generate any harmful chemicals that could cause your fish life. The bulb is exceptionally durable. Plus, it is easy to install and use.

One small problem is that the installer fussed with the fittings sometimes, but its efficiency remains unchanged.


  • Natural UV beam and chemical –free processing help this device work the best with the least harms to water and fish
  • Durable lamp helps product last long with working
  • The chemical-free procedure guarantees a healthy living environment or fish
  • It’s easy to install by anyone
  • It’s applicable or big fish tank   


  • The installer fussed with the fittings sometimes but it doesn’t slow down the effectiveness

Aqua Ultraviolet - 57 Watt 2 inch UV Sterilizer

Best UV Sterilizer for Large fish tank

Product description

  • Wattage: 57W   
  • Maximum Capacity: Fresh Water Sterilizer: 1,500-3,000 gallons, Flowrate - 3,200 gph for 30,000 µw/cm2SUP. Salt Water Sterilizer: up to 355 gallons; Flowrate - 1,066gph for 90,000 µw/cm2SUP>
  • Voltage: 110v / 60hz or - 240v / 50hz


  • This product is for large aquarium tanks.
  • Manufacturers publish the products with detailed information and specifications so that users can pick up proper products
  • Like any of Aqua Ultraviolet product, this Aqua UV 57 Watt works and takes effect only 3- 5 days after installation

Aqua UV 57W 2 inch Classic UV Sterilizer is the most powerful of in the Aqua Ultraviolet ’s collections of sterilizers. It comes to work with large ponds which are supposed to contain up to 3,000 gallons of water. When you purchase this product, you will receive a full set including light, transformer, and wiper.

This product has a high capacity to clear off a large area. It is also famous for the top-notch speed: only five days to clean a big fish tank. However, for a better result, you should re-use the UV sterilizer the second time for ultimate effect. 


  • The purchase comes with full set of the package, including the light and transformer and even the wiper
  • It helps users to get rid of algae string problem entirely and return the fish tank clear and beautiful look.
  • It’s able to treat a considerable area and eliminate all of the common issues with your fish tank in standard time up to 5 days


  • Quartz sleeve can leak
  • It’s supposed to take this one more time to take effects just because it has to deal with more significant area.

2. SunSun

SunSun - JUP-01 9W UV Sterilizer Submersible Filter Pump

SunSun JUP-01 9W UV Sterilizer Submersible Filter Pump

Product description

  • Wattage: 9W   
  • Maximum Capacity: Recommended for 75-gallon tanks with flow rate at 210 gallons per hour
  • Voltage: 110v/60hz or 240v/50hz


  • This sterilizer allows control water environment simply and effectively.
  • The producers use versatile technology, and the unit is the easiest to install among all of the sterilizers I have mentioned.  People do not need to connect with any tube or pump beside. However, this portable product is only useful in small tanks.
  • Sunsun designers have maximized exposure by a large mechanical pre-filter sponge and a built-in pump
  • The device is submersible so installation can happen vertically or horizontally.

The most favorable feature of this product is that all ready to go from the box. And I like the way it can be submarined, that helps a lot of people who are always struggling with setting-up. I would highly recommend you test your water quality. As common sterilizers, this product can clean up algae blooms, bacteria, or other water born parasites. However, This device is not yet a cure-all for all tank or pond problems. There are still backward that you should consider,


  • The all-ready product will become comfortable and attractive to many users
  • The submersible feature leaves the device work well with any ways of putting up
  • Perfect product for home fish tanks that you would love to have in the house


  • The devices work better only with a higher flow of water. However, it’s not convenient at all
  • It takes more time to work than other products, but it cleans up very well.
  • The bulb should be changed every year

SunSun - CUV-118 UV Sterilizer 18W Light Lamp Clarifier Pond Reef Fish Aquarium

SunSun - CUV-118 UV Sterilizer 18W Light Lamp Clarifier Pond Reef Fish Aquarium

Product description

  • Wattage: 18W   
  • Maximum Capacity: 2000 gallons or 75 gallons aquarium, Max Flow Rate: 600GPH
  • Voltage: 110v/60hz or 240v/50hz


  • In the version of more significant productivity, this device of Sunsun offer solutions to bigger ponds.
  • The lamp can handle maximum 650 gallons in an hour. And I think it’s possible for most of the users.
  • The product is easy to install, and people can set it up neatly in the ponds without difficulties
  • This UV sterilizer applies the simplest way to deal with free-floating bacteria.

The 18W SUNSUN light is a significant improvement for green water situation in the more extensive area. The price is affordable to most of the people. This product is for amateurs of UV sterilizers. It is easy to set up and use. Plus, the manual book is written incomprehensible language for first-time users. I also love its neat and compact design.

I would like to recommend this product to anyone who starts having their fish tanks.


  • It’s well made and easy to install. People can find it in solid look and neat design to set it up in any tanks you wish.
  • The affordable price tag for such a beautiful product at this point.
  • The instruction is presented no more comprehensible in English that helps users to install the product without troubles    


  • It takes more time for the first try.

SunSun - CUV-136 Aquarium UV Clarifier

SunSun - CUV-136 Aquarium UV Clarifier

Product description

  • Wattage:   36W   
  • Maximum Capacity:      9250 gallon
  • Voltage:     - 110-120V


  • A powerful device can pump up 1188gph; therefore, users can apply it to a huge pond.
  • This device can be connected to a filter in the fish tank to maximizing effects on preventing green water and maintaining optimal conditions.
  • The bulb ensures installation and maintenance to guarantee for a product existing for garden ponds

This is the most potent sterilizers in the collection of Sunsun, and we end up a product for ponds in a garden with super energy in cleaning up. More than that, this product can maximize effects by connecting with the filter of the tank. 

The materials are the key to this product. Adopting strong elements, the product ensures its durability and functionality. It can remove different varieties of bacteria and algae. Though the bulky look is a big drawback, I am convinced that the SUN CUV-136 Aquarium UV Clarifier will give you more bang for the buck.


  • Sturdy and stable materials help the product durable to use in the water
  • It works effectively in removing algae and harmful bacteria out of the tank.
  • Connection with filter assist a lot in maintaining the optimal conditions
  • The product is supposed to deal with large area or big fish ponds
  • The bulb is included in purchase    


  • There’s no quartz glass
  • Because of high productivity, the product comes with the bulky look

3. Coralife

Coralife - Turbo-Twist UV Sterilizers

Best UV Sterilizers for both freshwater and saltwater aquariums

Product description

  • Wattage: 3X - 6X - 12X   
  • Maximum Capacity: For freshwater or Saltwater aquariums up to 125 Gallons
  • Voltage: 110v/60hz or 240v/50hz


  • The product is designed in twist-flow, which is easy to handle
  • The mount on the top with brackets helps installation easier. Users can set up with lines or hang on as wanted.
  • The small indicator light is to notify working time. No big lamp attached. 
  • The product works well in both freshwater and saltwater aquariums.
  • The products come in 3 sizes; therefore, customers can choose a suitable size for a tank. Size 3X is usually recommended for 60-gallon tank.

I would love to introduce another brand name besides the Aqua Ultraviolet, the Coralife. The product I would like to introduce comes in a powerful look.

People can take advantages of this Coralife Sterilizers in removing unwanted free-floating algae, parasites and bacteria. The twist flow design is new to the market at the moment, and this unique features can increase exposure to water and, as a consequence, perform better in the cleaning job.

The limited productivity made this sterilizer one of the best for home fish tanks. You cannot see its effectiveness to the fullest if applying in a huge pond. Furthermore, choosing the right pump is necessary


  • It has a modern design: twist-flow which helps exposure and penetration become more effective
  • With bracket, the product is easy to handle in different ways
  • Multiple sizes are provided for appropriate fish tanks


  • Sometimes, leaky electrocution trap happens
  • The metal cover can get rusted in salt water, so I do not recommend this product for salted aquariums in case you have a protection plan

4. AA Aquarium

AA Aquarium Green Killing Machine Internal UV Sterilizer with PowerHead

AA Aquarium - Green Killing Machine Internal UV Sterilizer with Power Head

Product description

  • Wattage: 9 W   
  • Maximum Capacity: 53 gallons is recommended the volume to deal with
  • Voltage: 110v/60hz or 240v/50hz


  • AA Aquarium is applying the first ranked submersible that comes with UV Radiation Filtration of 254nm wavelength. Using this in the fish tank can protect the fish the best because no chemicals in use and toxic substances left.
  • Even the product comes with low wattage; AA aquarium has elevated it with premium sponge inclusive. Now, you’ve got a sterilizer with a pump rate of 200l/Hr. Therefore, this device can deal with 53 gallons of waters
  • The LED signal doesn’t make a big deal besides notification about when you should change the bulb Even though this doesn’t matter about sterilization but not many brands think of this idea.

The AA Aquarium joined the market with some products such as this Green Killing Machine Internal Sterilizer with Power Head. They come in three level of wattage so I would like to talk about the 9W only

This state-of-the-art AA Aquarium Green Killing Machine help us to remove cloudiness, impurities & bacteria and stops stain such as mold, yeast, and pathogens from growing, along with clear step-by-step guidance I bet no one could have difficulties in establishing. Here is Green Killing machine instructions.


  • No chemicals used
  • UV filtration offer pro radiation of UV but still safe in sterilization
  • Simple and neat design for more accessible and simpler establishment
  • Ultra powerful pump can pump up 200 liters of water an hour
  • Convenient LED notification helps users save a lot of time to decide when bulb should be changed.   


  • Only fit for small tanks-   

5. Aquatop

Aquatop -  PF15-UV Hang-On Filter with UV Sterilization

Aquatop - PF15-UV Hang-On Filter with UV Sterilization

Product description

  • Wattage: 3.5W for UV power but 5W for bulb
  • Maximum Capacity: For 15-gallon aquarium
  • Voltage:  110v/60hz or 240v/50hz


•    The ultimate design is crystal clear which seems perfect for settling in the water

•    Independent UV light power switch.

•    People can adjust the flow rate to suit with fresh and salt water

•    It’s established with the tank on the back. This installation style can help with adjusting the surface skimmer and promote gas exchange

•    The UV is PFUV015, just enough to eliminate algae blooms but no harms to the fish

The product is just OK for a small tank, but not for bigger ponds. It performs the best with UV, but not filter chamber where filter mechanical is poorly set-up. I like the “hang on back” design and crystal clear because it looks great with water.


  • Excellent and useful filter for small tanks
  • The adjustable flow rate for appropriate water
  • Nice combination of UV and filter  in a device


  • Take quite long to work 9 (about three days)
  • The filter function is not outstanding
  • Not capable of a bigger fish pond


GRECH -  CBG-800 5W UV Sterilizer Hang-On Back Filter

GRECH - CBG-800 5W UV Sterilizer Hang-On Back Filter

Product description

  • Wattage: 5W   
  • Maximum Capacity:  20 to 50 Gallons with an adjustable flow rate of 211gph
  • Voltage:  110v/60hz or 240v/50hz


  • The products come with a unique design from other everyday products on the market
  • It contains Adjustable Filter and Surface Skimmer with helps a lot in eliminating films of the surface.
  •  The product is a combination of Biological and mechanical filtration. You can see the black box in the back, and it’s supposed to contain active carbon and bio media to help with clearing water.

Another 'Hang-On-Back,' in the list but this one have some differences. Firstly, the function. While The above sterilizer is limited in filtering, this one is better at it thanks to the combination of active carbon box. 

Besides, there some other pros and cons that we should analyses. The design of this product is worth to mention. It features the hang-on-back design that is easy to install. It offers a useful surface skimmer to reduce oil in the tank glass. However, it looks quite bulky and can only work with small tanks.


  • The “hang on back” design made this product easy to use and settle
  • Easy and flexible water flow
  • Useful surface skimmer because it helps in reducing oil happening in tank glass


  • The bulky look
  • Only for small tanks

Best Aquarium UV sterilizer: Buying Guide

Before getting to know the most wanted UV sterilizers, consumers should keep in mind some definitions and features that help to identify the most suitable for their own house.

What is a UV sterilizer for fish tank?

UV sterilizers are a type of sterilizers which eliminate pollution in fish tanks by UV. The equipment contains a tube of ultra-violet light which produces UV beam coming through bacteria cells.

Ultra-violet light is known harmful and can cause cancer. However, if used cautiously, UV sterilizers will neither harm your fish nor other aquarium creatures.

How many types of sterilizers on the market?

Based on what’s on the market at the moment and available sources, there are three popular types of UV sterilizers as below:

Dry heat sterilizers

The dry heat sterilizers cope with microorganisms at a higher temperature. Because of the heat effect, people regard dry heat as an effective and safe type of sterilizer. Heat treatment doesn’t affect edges of the tank, cause rust on the metal surface. There are two popular dry heat sterilizers: traditional 'toaster oven' style and COX Rapid Heat.

Steam sterilizers

Steam sterilizers work on temperature, pressure and time basis. It works faster with higher temperature and pressure. However, this method can cause edges rusted or dull. The autoclave is still the bestselling of all type sterilizers.

Heated chemical vapor sterilizers

One of the advantages of heated chemical vapor sterilizers is a short cycle time. However, it usually makes corrosion or rust. It needs cleaning as soon as possible after use in order for a longer lifecycle. This one is not recommended for plastic tanks.

Why should people equip UV sterilizers in fish tanks?

Raising fish in the tank cannot avoid dust and bacteria because of the animals and other plants living in the tank. Therefore, frequent cleaning is necessary for any tanks. A UV sterilizer could help a lot with filtering and purification based on the following reasons:

-    UV Sterilizers help to eliminate bacteria, algae, and other water nuisances. The devices work on UV beam so that it minimizes harms to other materials in the tank such as edges, stone decoration, plants, and metal parts.

-    UV sterilizers can operate well in both freshwater and marine water. Therefore, you do not have to change sterilizers in case you change the fluid. The devices keep water crystal clear.

-    It cannot kill fish or other creatures such as corals which are something happen in domestic fish tanks. However, the UV beam may cause pressure on fish by an effect on nerve system, but it depends.

What should you concern when choosing a best UV sterilizer?

There are some fundamental features that you should look at in choosing a UV sterilizer for either home or industrial fish tanks. The most important specifications are as below:

Regarding the device itself:

Size of UV: Even though UV sterilizers can be useful in most of the tanks, an appropriate choice of size can maximize the productivity. Different UV sterilizers are made in a variety of UV size. For example, you cannot use a small UV sterilizer for a colossal tank; it’s not enough to tidy up every inch of the tank as you wish. Or a massive sterilizer for a small tank is such a waste.


How long it takes a UV sterilizer to break cells or DNA? The matter comes serious because that means when the sterilizers work in your tank. UV killed Ich or other bacteria in the tank by breaking down the cell, and the process doesn’t happen in a second. Let’s image how long your skin gets burn under the sun? Maybe some hours, perhaps half of an hour. But people skin cannot get burn in a minute. The process happening in the tank with UV sterilizer is precisely the procedure of how people get a sunburn by sunlight. 

UV Radiation

The intensity of UV radiation matter how much bacteria get killed. The measurement of UV radiation comes by uWs/cm2 (Microwats of energy on a centimeter square) (ref). 336,000 uWs/cm2 is minimum intensity we can accept with the hope that the device can eliminate Ich.

Because Ich is the hardest to kill. The mentioned intensity is out to target in choosing UV sterilizers. As if the device can deal with Ich, any other algae and bacteria are on the point.


Recently, manufacturers use to publishing exposure rate with the product, partly to advertise how useful the device is. You should pay more attention to exposure rate along with a low rate and especially in salt water.

Knowing the exposure rate can help people to choose suitable products to the tank and up to users’ requirement.


People should know a statement that radiation goes down when the flow goes up. It happens because of fast flow can reduce connection to the exposure of radiation.

That means you do not need a 336,000 vWs/cm2 sterilizers because UV radiation could be enhanced by slow down water flow. 

Size the tank

Size of the container you are targeting at influences on the work of sterilizers indeed. Even you have done the math about radiation and exposure. How big is the tank? You should have another math to solve but only by estimate.

Regarding other factors such as:

The type of organism

As mentioned above, UV radiation can deal with certain creatures at a certain level. Using UV sterilizers or not depends on the organisms you want to cope with. Common algae or bacteria are supposed to decrease because of UV. However, something big such as protozoa seems to get no harms from radiation treatment. Even marine Ich, they get influenced only in the certain level of radiation. 

Cleanliness of Water

If the water is crystal clear, The UV sterilizers can work better.  We understand that making water clear is the reason why UV sterilizers are bought from the stores. However, light cannot penetrate in water if it’s not clear enough.  You can enhance cleanliness by biological or mechanical methods before installation of UV sterilizers.

Dwell time

The job gets done when the light penetrates in the water. Hence, effectiveness increases by a longer time of exposure. You can improve this job by the flow of water. I would like to recommend a waterfall.

Purpose of use

Anyone who wants to have a UV sterilizer should know that it’s not a filter. UV sterilizers are considered a kind of insurance for the tank when things haven’t become serious yet. Users should accept that, but they take care of a majority of the bacteria spreading through the water or fish to fish. They work with expectation provided you install in proper tanks with appropriate situations.

And since not all sterilizers are well evaluated equally, and there is nothing perfect for any tanks, there are choices to choose from.

Let’s move on to the next part. I can show you some suggestions available. With a wide range of brands and intensity, I hope some can fit your circumstances.

How UV Sterilizer works

A UV sterilizer cleans up the fish tank by operating of UV beam. It has got a look of the bulb but stays secured and submerged in the water. Bacteria and organisms in the water are removed by eradication which happens when the fluorescent light hit the water.

The light touches the water surface and kills free-floating creatures on the water; therefore, the fish are safe under the water. The beam can go through living cells and mutate. Hence, when coming through micro-organisms, the device can stop those creatures from growth or reproduction.

As mentioned before, UV sterilizers can work in any water and almost all types of tanks. Nevertheless, small tanks can help sterilizers in maximizing their effects since the frequency of bacteria or algae’s appearance in a smaller area is higher.

To see how effectively they work, users should install UV sterilizers in small tanks with a high density of fish. Putting them in larger brand new tanks will take time because bacteria haven’t had time to establish yet, including good bacteria and aquarium creatures like corals.

Frequently Asked Questions (FAQs)

UV sterilizer for freshwater aquarium is necessary?

If you are a fish lover, chances are you have heard of UV sterilizers. UV sterilizer emits ultra-violet light to protect the aquatic ecosystems by killing single cell entities. It helps eliminate algae, bacteria, and parasites that pollute the water and are harmful to your fish.

It is apparent that ultra-violet light is dangerous; therefore, many fish lovers wonder whether it is necessary to have the UV sterilizer for their fish tank or not. In fact, it is a thorny issue among fish lovers that attract divisive opinion. Some people argue that the UV light is way too threatening for their beautiful underwater creatures. Some say it is generally safe to use.

Personally speaking, I would say if you use a UV sterilizer with care and caution, it will undoubtedly bring more bang for the buck since it keeps the water clean and prevent fish death. UV light will not be a significant threat to either your fish or your invertebrates.

How long for a UV sterilizer to work?

UV sterilizers emit UV light used to kill of microorganism in the surrounding area. The UV light with a wavelength of 254 nanometers modifies the DNA and shorten microbes’ lifespan. When it comes to the proper length for the sterilizer to work, there are several factors to consider.

The first notable feature you have to take a look is the flow rate. Apparently, the flow rate has a significant influence on the efficiency of UV sterilizers. UV light should stay longer underwater to increase its killing power. People call this “dwell time” or contact time. The slower the flow rate is, the longer the contact time expands.

One thing that could affect the length of sterilizers’ efficiency is the bulb. The bulb with higher capacity (wattage) produces more light, thus increasing the chance to kill harmful elements.

When to replace UV sterilizer bulb

The bulb is probably the essential component of UV sterilizers because it generates UV light. If you want to know the amount of light the sterilizer can produce, merely take a look at the wattage of the bulb. In other words, the wattage is equivalent to the amount of UV light.

Bulbs, unfortunately, have a limited lifespan. Their effectiveness lasts as long as six months, and after that, you are required to change to a new one. This is because the ability to generate UV light will decrease sharply by 50%. Some manufacturers will recommend you to change the bulb sooner or later depending on each model.

If you want to extend the use of your bulb? Get yourself a double-capacity bulb. In the next six months, when the bulb gets weaker by 50%, it still has enough strength to emit a required amount of UV light.

When to use UV sterilizer

So when should you use UV sterilizer? As I mentioned above, this product is essential to keep your tank clean and protect the fish life. Research on UV radiation shows that within an appropriate range (from 300-400 nanometers), this seemingly dangerous light could oxidize essential molecules for water such as phosphates, nitrogenous compounds.

Besides that, UV sterilizers help clean off algae, bacteria, parasites, and other microorganisms. If you keep sea creatures such as sea horse, it is a must to have a UV sterilizer.

You can use this product to clear the water generally depending on the tank cleaning schedule. However, don’t want until the algae have already popped up because it could be too late. It is also not necessary to use to daily, though it could be helpful. 


I can deny the importance of UV sterilizers once I look at what they have to offer. UV sterilizers, for me, are heroes of the fish lovers since they bestow so many useful features. If you want to increase the cleanliness and decrease the death rate of your beloved fish, you should buy a sterilizer. There are 12 products that I consider the best UV sterilizers in the market. I hope that you will find this article useful, and I do wish what you find in this writing will be helpful for you once you make your choice.


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