The 10 Best Aquarium UV Sterilizers in 2024

The 10 Best Aquarium UV Sterilizers in 2024

If you’re serious about fishkeeping, then you know how important it is to maintain good water quality in your aquarium. It’s probably the single most important thing that all other aspects of fishkeeping rely on. Water, after all, makes up your aquarium’s whole world.

However, you also probably know how difficult it is to keep your tank’s water conditions pristine all the time. There are many things that affect water quality, such as pollution, nutritional imbalances, and sudden, unexplainable algae bloom.

That’s where aquarium UV sterilizers come in. If you’re already feeling drained (pun intended) from having to keep your water quality in tip-top shape week after week, then this nifty little device will take a load off your shoulders.

But how exactly do you choose which aquarium UV sterilizer to buy? In this article, we’ll discuss everything you need to know about buying the best aquarium UV sterilizers in 2024.

Factors to Consider When Buying Aquarium UV Sterilizers

Before we get into the specifics, let’s first discuss the basic factors that you have to consider before you purchase your first aquarium UV sterilizer.

Sterilization Level

The first thing you need to decide before even looking at UV sterilizer units is the level of sterilization that you need for your tank.

Basically, there are three sterilization levels, with each one corresponding to different issues in your tank. If you’ve got algae blooms, for instance, getting a lower level sterilization unit may be enough. If you’re dealing with harmful microbes, however, this may not be enough.

If you want to learn more about this, you can take a look at its own section in our full guide below.

Tank Dimensions

Secondly, you have to know the dimensions of the tank where you’re going to install the UV sterilizer.

This is important because the dimensions are typically directly related to the volume of water that the tank can accommodate. Remember, different products have different disinfecting capacities. To make sure that your whole tank is going to receive thorough UV filtration, the volume of the tank must match the capacity of your chosen sterilizer unit.

UV Light Strength

Somewhat an extension of the previous factor, you have to know how strong your UV light is and its filtration capacity. As mentioned, you have to know the volume of your tank to make sure that the UV unit has enough capacity to filter the water as it passes by.

For more details about the suggested wattages of UV light and their capacities, you can jump further down this guide.

Unit Type

There are several types of aquarium UV light sterilizers on the market right now, such as hang-on, in-line, tray-type, tube-type dry bulb, and tube-type wet bulb. Each type has its unique set of traits that you should take a look at when choosing the best product for your needs.

For more details about the different types of aquarium UV sterilizers, you can read all about them in their own section below.

Additional Features

Different UV sterilizer brands are going to have different features. Some products come with a pump, some with a direct-contact feature, while some come with easy installation and specialized add-ons. You need to think about the features that will suit your needs the most.

For more information about the specifics of what particular features are critical to keeping an eye on when shopping for UV light sterilizers, you can head to its specific section below.

With that out of the way, let’s proceed to the 10 best aquarium UV sterilizers you can buy in 2024.

Top 10 Best Aquarium UV Sterilizers 2024

1. Best Overall: Coodia Internal UV Light

Coodia Internal UV Light

Editor’s Rating:

Why we like it: Coodia’s internal UV light is good for large aquariums up to 75 gallons, reliably breaking down harmful microbes to keep your aquarium water clean, clear, and healthy – all at a very reasonable price.

Quick Facts:

  • Type: Tube-type dry bulb
  • Capacity: 75 gallons
  • Wattage: 5W UV
  • Add-ons: 5W pump

Coodia’s offering to the game is a 5W UV light that easily punches above its class. Although it’s a relatively lesser-known brand, this internal UV light shows performance and quality that reflects great craftsmanship.

The unit shows improvement in large amounts of water within hours, managing to eliminate microbes within your tank in just a couple of days. It has a large capacity that can handle up to 75 gallons of water. It’s also very easy to set up and comes with an efficient pump that has just enough water flow for thorough sterilization as well as additional oxygenation to the aquarium. All that for a competitive price.

That said, there seem to be some quality control issues when it comes to the product, at least based on consumer reviews.


  • Works fast
  • Large capacity
  • Easy setup
  • Includes a pump
  • Very cost-effective


  • Quality control issues

2. Best Premium Pick: Coralife Turbo-Twist UV Sterilizer

Coralife Turbo-Twist UV Sterilizer

Editor’s Rating:

Why we like it: Certainly one of the most unique offerings on this list, the Coralife Turbo-Twist features its very own Twist-Flow technology for extra exposure and thorough UV sterilization.

Quick Facts:

  • Type: Tube-type wet bulb
  • Capacity: 150 gallons
  • Wattage: 5, 9, 18, 36 W
  • Add-ons: Indicator light

Coralife delivers an innovative approach to UV sterilization with its unique Twist-Flow technology. Inside the high-quality plastic housing where the water goes are extra ridges that direct the flow of water to twirl around the bulb, prolonging light exposure and increasing the UV sterilization rate.

Turbo-Twist comes in 4 varying sizes with 4 varying power requirements to cover all aquarium sizes, including large tanks of up to 250 gallons. It even features an indicator light to notify the user of the current status. The UV light bulb itself is made from high-quality quartz glass that is not only sturdy but is also ultra clear.

However, this product is significantly pricier compared to other brands, because of its use of premium materials. It also doesn’t come with its own water pump and requires a lot more pressure to get the flow rate going. Lastly, it’s rather inconvenient to set up because you have to hook it to a separate filter unit.


  • Features unique Twist-Flow technology
  • Comes in 4 different wattages
  • Bulb is made of premium quartz
  • Has an indicator light


  • Very expensive
  • No water pump included
  • Inconvenient to set up

3. Best Budget Pick: Coospider Aquarium Clean Light

Coospider Aquarium Clean Light

Editor’s Rating:

Why we like it: If you’re looking for reliability on a limited budget, Coospider’s bare-bones but powerful UV light sterilizer can deliver exactly what you need.

Quick Facts:

  • Type: Tube-type wet bulb
  • Capacity: 150 gallons
  • Wattage: 11W UV
  • Add-ons: N/A

Don’t let its appearances fool you – Coospider’s quartz bulb submersible UV light delivers value equalling that of the big brands.

Without the limitations of water flow and the pump, this unit can clarify practically anything. Thanks to its very long cable and IP68 waterproof rating, you can place it almost anywhere inside the tank. You can place it on the hood as a light source or as part of a filter system. Its UV light is ultra-bright and can sterilize your tank to a good degree. If you don’t mind not having a lot of features available to you, then Coospider’s UV sterilizer is a great addition to any aquarium setup.

However, it does come with a few caveats. For one, since it’s a wet-type bulb, it can’t be placed in the water directly. You have to either put it over your tank or within a sump setup. Wet bulbs pose a greater risk of electrocution, so you need to be very careful when handling them during maintenance.


  • Very affordable
  • Ultra-bright UV light
  • 175cm long cable
  • IP68 waterproof rating


  • No additions or special features
  • Needs to be put in a sump tank or similar

4. Best for Medium Tanks: SunSun 9W UV Sterilizer

SunSun 9W UV Sterilizer

Editor’s Rating:

Why we like it: SunSun is a well-known name when it comes to the aquarium industry. That’s no surprise, especially with this high-capacity, high-powered, microbe-destroying UV sterilizer.

Quick Facts:

  • Type: Tube-type wet bulb
  • Capacity: 75 gallons
  • Wattage: 9W UV
  • Add-ons: Built-in pump

SunSun’s 9W UV sterilizer is capable of clearing up to 75 gallons of water, which makes it best suited for small to medium-sized aquariums. If your tank is suffering from green water, this unit can help you with your problem within just 12 hours of continuous light exposure.

The product comes in a boxy, all-black design that is characteristic of SunSun’s brand. Even though it’s not the prettiest, it’s certainly one of the most effective out there when it comes to performance. You can position it both vertically and horizontally to hide it in your tank or make it blend in. It’s very versatile, suitable for both freshwater and saltwater aquariums as well as small ponds. It also has its own built-in pump and a pre-filter sponge.

That said, we found two main issues with this unit. The first one is the strong pump flow. This may be a problem for reef tanks or tanks with fish who are used to calmer waters. Two, the UV light is so strong that leaving it on for more than 12 hours at a time can melt plastics, so be sure to keep your eye out on the time if using this unit.


  • Highly versatile
  • Effective sterilization
  • Comes with a built-in pump
  • Adjustable flow rate


  • Not for reef or similar tanks
  • UV light very strong

5. Best in Power Saving: SunSun JUP-02 5W UV Sterilizer

SunSun JUP-02 5W UV Sterilizer

Editor’s Rating:

Why we like it: Compact and versatile, you can use the SunSun JUP-02 as a standalone inside your tank or as an attachment to filtration systems.

Quick Facts:

  • Type: Tube-type dry bulb
  • Capacity: 40 gallons
  • Wattage: 5W UV
  • Add-ons: Pump, pre-filter sponge

Don’t miss the quality that this SunSun product brings to the table or you’ll regret it. If you’re looking for high-performance UV sterilization for low power consumption, then this is the right unit for you.

Built mainly for small to medium-size tanks, this 5W unit is made with the same reliable quality that we’ve come to expect of SunSun. It has a plain boxy and mostly-black design, but at least it doesn’t steal attention away from your aquarium. Its solid plastic construction is also durable enough to withstand most conditions. It’s capable of sterilizing quite a large volume of water, considering that its ultra-bright UV bulb only consumes 5W of power. It features an easy plug-and-play setup and comes with a pre-filter and a 132 GPH pump.

That said, if you have a small tank, you might have a harder time with this unit since its flow rate may be too strong and powerful, despite the low wattage. This is especially true if you’ve got a reef tank or other calmer tanks.


  • Power-saving
  • Powerful 5W UV light
  • Solid construction
  • Convenient setup


  • Plain and boxy design
  • Flow rate too strong for small tanks

6. Best for Large Tanks: Roxin Aquarium UV Light

Roxin Aquarium UV Light

Editor’s Rating:

Why we like it: A relatively unknown brand in the aquarium UV game, Roxin offers products that are capable of high-quality performance at a decent price.

Quick Facts:

  • Type: Tube-type wet bulb
  • Capacity: 1,000 gallons
  • Wattage: 5, 7, 11, and 13W
  • Add-ons: Clips, adapter

If you’re looking for an aquarium UV sterilizer that can moonlight as a small-pond purifier, then Roxin’s offering is perfect for you. It has 4 wattage variations that can cater to anything from a large aquarium to a mid-sized pond, making it the best choice for large tanks. With this unit, you can rest assured that even the greenest, most algae-infested water can turn crystal clear within just hours.

Just like Coospider’s UV sterilizer, the light bulbs used in this product are the wet type, which means they don’t have housing. You can house the bulb in your aquarium’s canopy or you can place it in a sump tank that contains no fish. Once there, all you have to do is turn it on and let it run. Do take note that because it requires a lot of power, Roxin recommends just using it for 3-4 hours every 2-3 days. This may seem rather restricting, but we found that this is usually enough to successfully get rid of any issue you may be having with your tank water.

That said, its being a wet type bulb does present more limitations and risks than its more advanced competitors. For one, you can’t put it inside your main tank since your fish could get accidentally electrocuted. Ideally, you should put it in a sump tank, as it needs water to stay cool for maximum performance. This, in turn, could be a bit limiting for some aquarium setups.


  • Relatively affordable price
  • Comes in 4 wattage variations
  • Can handle large tanks and ponds
  • High-powered unit


  • Requires you to limit usage to a few hours
  • Can’t be put directly in tank for safety purposes

7. Best No-Frills: Yadico Aquarium 9W UV Light

Yadico Aquarium 9W UV Light

Editor’s Rating:

Why we like it: If you’re looking for a basic, no-frills approach to UV sterilization that provides plug-and-play convenience, then Yadico’s 9W internal submersible UV sterilizer is your best bet.

Quick Facts:

  • Type: Tube-type dry bulb
  • Capacity: 75 gallons
  • Wattage: 9W UV
  • Add-ons: Indicator light, pump

Capable of sterilizing up to 75 gallons of water within 72 hours, Yadico’s offering in the aquarium water sterilization industry is certainly no slouch when it comes to performance.

This unit has a bright, long-lasting UV bulb that is efficient in killing all sorts of microbes. Its housing comes in an understated design that is easily hideable within the interior of your tank. It comes with several additional features, such as an indicator light and a pump. Setup is very convenient and you can get the unit up and running in just a few minutes.

However, the flow is still not as strong as the other units on this list. Even the 5W submersible unit from SunSun has a much stronger flow than this even though it has a lower wattage. It also makes a significant amount of noise during operations.


  • Affordable
  • Fast and convenient setup
  • Comes with its water pump
  • Has an indicator light


  • Underpowered pump
  • Generates noticeable noise

Ledgle Aquarium Submersible UV Lights

Editor’s Rating:

Why we like it: If you’re looking for a single brand to cover the sterilization needs of all your tanks of various sizes, then Ledgel has you covered.

Quick Facts:

  • Type: Tube-type wet bulb
  • Capacity: 300 – 1,000 gallons
  • Wattage: 5, 7, 9, 11, and 13W
  • Add-ons: Clips, adapter

Providing more in terms of wattage choices than Roxin, Ledgel is definitely the most versatile unit on this list.

The added wattage options are a bonus especially for larger aquariums, as this unit can sterilize tanks with capacities of up to 1,000 gallons. It’s also very easy to use. All you have to do is press a switch and you can have a clearer tank within 30 minutes, as long as you make sure that the unit you choose matches your tank’s capacity. Build-wise, it’s made out of superior-quality silica glass that won’t easily break and retains its clarity for a long time.

However, upon careful inspection, it appears that the wirings and soldering on the product are quite fragile and weak. This particular type of bulb is also riskier for fish in general if you don’t house it properly in a separate sump or overhead tank.


  • Easy and convenient to use
  • Plenty of wattage choices
  • Great for larger aquariums
  • Made of durable and high-quality glass


  • Fragile wirings and weak soldering
  • Riskier type of bulb

AquaUltraviolet Advantage Aquarium UV Sterilizer

Editor’s Rating:

Why we like it: If you’re going for a minimalist theme, or you just want something that takes up the least space in your tank, then AquaUltraviolet’s in-line UV sterilizer is for you.

Quick Facts:

  • Type: Tube-type in-line
  • Capacity: 500 gallons
  • Wattage: 15W
  • Add-ons: PVC housing, adaptor

AquaUltraviolet’s in-line UV 15W aquarium UV sterilizer delivers a powerful punch in such a small frame. With dimensions of just 12¼” x 4″ x 2 ¾,” this sterilizer could fit even in the tightest places in your setup.

The 15W UV bulb delivers intense light that can kill off all microbes and viruses in your water within a short span of time, despite the unit’s petite size. Installation possibilities are practically limitless. For instance, you can hook it up to the return tube of your external filter, or even rig it right beside your HOB filter. Using it is also very easy. You only have to flip a switch and your water will be crystal clear in hours. The unit has an impressive lifespan and can survive frequent use for a long time as long as you don’t let it overheat.

However, it does consume a bit more electricity than usual compared to competitors of the same capacity. The PVC plastic housing is also a little thin, although we haven’t found any major problems with it. Lastly, the unit doesn’t come with mounting gear so you have to buy whatever you need yourself.


  • Intense UV light
  • Compact design for easier storage
  • Easy and convenient to use
  • Long-lasting


  • PVC is a little thin
  • Relatively power-hungry
  • Doesn’t come with mounting parts

10. Best Budget in-Line: Flexzion 9 Watt UV Sterilizer Light

Flexzion 9 Watt UV Sterilizer Light

Editor’s Rating:

Why we like it: Want top-notch performance without paying for premium prices? Flexzion can do most of what bigger brands can do for a more affordable price.

Quick Facts:

  • Type: Tube-type in-line
  • Capacity: 50+ gallons
  • Wattage: 9W
  • Add-ons: PVC housing, hose adaptor

There aren’t many in-line UV sterilizers on the market, which is why Flexzion’s 9-watt sterilizer stands out among the crowd. You can hook it up to the waterlines of your external canister filter to clear your water in no time. Unlike wet-bulb types like Ledgel, Roxin, and Coospider, it has the benefit of being hidden away from view while ensuring the safety of your fish.

Since the product is housed in durable PVC plastic, you don’t have to put the bulb directly into the water. You only have to rig the waterline of your filter into the unit’s inlets to rid your water of pesky microorganisms. It can clean up your water anywhere from a few hours to a few days, depending on your tank’s volume. It’s not as advanced as the other products on this list, but its performance-to-price ratio still makes it a nice pick for those who want to try the in-line type of sterilizer.

That said, it’s much harder to install than other types. If you’re planning to DIY its installation, you should have basic plumbing skills and a lot of patience. Similarly, the unit is very difficult and time-consuming to clean properly.


  • Superior quality for great value
  • Unit can be hidden from view
  • 100% safe for fish


  • Difficult to install and maintain

The Ultimate Guide to Aquarium UV Sterilizers

marine aquarium corals under uv light

If you want crystal-clear water without the hassle of a weekly water change, then you should take a look at aquarium UV sterilizers.

A good UV sterilizer can help you maintain a clean tank by breaking down harmful particles or organisms that cloud up your water.

However, there are a lot of products out there with their own features, advantages, and disadvantages. In this ultimate guide to buying the best aquarium UV sterilizers, we’ll tell you everything there is to know about this helpful addition to any tank.

What Are Aquarium UV Sterilizers?

Aquarium UV sterilizers are devices that make use of ultraviolet (UV) light bulbs to help maintain your tank’s cleanliness. They do this by ridding your aquarium of any potential outbreaks or unwanted particles. These free-floating microscopic organisms are not only potentially harmful to your pets, but they’re also often the culprit in making the water cloudy and unappealing.

UV light is extremely effective against bacteria, algae, microbes, and other pathogens inside your tank. Typically, UV sterilizers work in a light-and-pump tandem, with the pump working to pass the water through the light so that the light can then treat the water. Once the water passes through the UV light, every unwanted organism in it either gets killed or sterilized, preventing further issues.

Thankfully, UV light is not strong enough to harm your plants and animals, so you can use aquarium UV sterilizers safely without worries.

Benefits of Using Aquarium UV Sterilizers

Unsure whether to purchase one for your aquarium? Here are the benefits of using aquarium UV sterilizers in your tank.

1. Keeps Your Water Crystal Clear

Algae, as well as other free-floating microbes, thrive on the extra nutrients within the water column, such as phosphorus and nitrogen.

If there’s a huge nutritional imbalance within your system, these microbes are likely to take advantage and multiply like crazy, which results in cloudy or deep green water in your tank. This is a sign that the microorganisms thriving in your water column have become so abundant that you can now see them physically.

However, most microorganisms in your tank are very susceptible to UV light radiation. UV light causes cell mutations that prevent them from reproducing and ultimately end up killing them. This ensures that your water remains crystal-clear at all times.

2. Prevents Your Fish From Getting Sick

The free-floating stuff in your water column isn’t just made out of algae – there’s also a fair amount of bacteria, viruses, and pathogens in there.

If your fish have a low immune system, like when they’re stressed, for instance, then the abundant amount of nasty stuff in the water can easily latch on to your fish and make their condition worse.

UV sterilizers can help prevent this from happening. Because sterilizers can safely kill all kinds of harmful things in the water, your fish are less likely to get sick from them. This means that installing a UV sterilizer can save you the cost, effort, and grief of caring for and even potentially losing sick fishes down the road.

3. Reduces Maintenance Labor

All tanks need regular water changes to prevent ammonia build-up. Too much ammonia in the water can kill your aquarium’s inhabitants. But as much as we love fishkeeping, it’s undeniable that regular cleaning and water changes can get tiring too as time goes on.

If you have a UV sterilizer installed, however, you don’t need to do water changes as often since the light already keeps the water in a good condition. Since UV light eliminates algae as well, you also have to clean less frequently.

Types of Aquarium UV Sterilizers

There are five basic types of UV sterilizers, all of which have varying strengths, weaknesses, installation methods, and UV application.


This type of UV sterilizer has a UV bulb hanging about an inch above a tray of slowly flowing water. The sterilization happens when the water passing underneath the bulb gets exposed to UV light.

Tray-type sterilizers are fairly inexpensive and easier to maintain than other types. However, they’re not as efficient and can be somewhat bulky in size, especially when installed in small aquarium setups.

Tube-Type Wet Bulb

Cylindrical in design, tube-type wet bulbs like Coralife Turbo-Twist and Coospider’s Submersible Light has a UV-emitting lightbulb fully dipped into the water. This makes the design compact and space-efficient. It can also sterilize the water faster than a tray-type sterilizer since the bulb shines UV rays on all sides of the tank.

That said, many aquarists are careful with this type since it’s also the most prone to electric shocks. Understandably, they’re completely waterproof, but accidents do happen sometimes. Remember to always turn off the sterilizer first if you’re planning to dip your hand into the tank.

Tube-Type Dry Bulb

Tube-type dry-bulbs like SunSun JUP 02 are similar in principle to the wet-bulb, but as the name implies, the bulb remains dry throughout. This is because the UV light bulb is encased inside a quartz sleeve, which doesn’t let the bulb itself touch the water but still allows the UV light to shine through.

Although it’s much safer to handle and maintain than the wet-bulb type, it also typically costs much higher.

Hang-on Lamps

Hang-on lamps are a type of UV sterilizer that is suspended on top of your aquarium to shine UV light down below. Sometimes, this type substitutes normal aquarium lights, especially in certain saltwater aquarium setups where UV light is important for coral growth. There are also varieties that you can insert in a hang-on-back filter and some which you can clip to the outflow of a waterfall filter.

The only downside to hang-on lamps is that they don’t do as well in the sterilization aspect as other types on this list.


Often considered the most flexible type of UV sterilizer, in-line sterilizers like AquaUltraviolet Advantage and Flexzion Sterilizer Light are installed directly into your existing filter. Often the last process that the water passes through before it’s directed to the tank, inline sterilizers can be kept outside of the aquarium as a part of a canister or HOB filter. They are often tube-types for the most efficient water sterilization output.

The biggest issue with in-line sterilizers is how hard they are to install and maintain. If you’re not big on maintenance, you should steer clear of in-line types.

Things to Keep in Mind When Choosing UV Sterilizers

To choose the best UV sterilizer for your need, you’re going to have to compare each brand spec-by-spec. This section will tell you the crucial things that you need to be mindful of when choosing your next UV sterilizer.

Sterilization Level

Sterilization level refers to the sterilizer unit’s power to eliminate harmful particles in your tank. The three main levels are clarifying, level 1, and level 2.

Regular sterilizers are typically referred to as clarifying sterilizers. These units are strong enough to remove algae from your tank as well as anything else that can lead to green water, but not the more harmful microorganisms that can cause diseases.

Level 1 sterilizers are much better at killing bacteria as well as viruses. They still can’t kill all microorganisms, but their flow rates are certainly strong enough to keep your tank water clean for the most part.

Lastly, level 2 sterilizers are the strongest sterilizers out there, at least when it comes to the ones that you can use at home. They don’t need high flow rates to effectively kill even the toughest microbes in your tank. Do take note, however, that some bacteria are naturally more resistant to UV.

UV Transmittance

Aquarium UV sterilizers can only kill the microorganisms in your water if the light can actually reach them. For instance, if the water is too cloudy or dirty, then you’re going to have slow-going sterilization as the light won’t be able to properly penetrate the water.

This is called transmittance, which is measured on a scale from 0-100%. 0% means that the light isn’t able to penetrate the water at all, while 100% means that there is nothing in the way of the light.

Transmittance is most affected by how clean or dirty the water is since UV light will not pass through small particles floating in the water. It’s also affected by salinity, as freshwater is easier to penetrate by light than saltwater. However, sometimes it’s also affected by objects blocking the way, like aquarium decor or plants.

To optimize the UV penetration, it’s best to place your sterilizer in an area where only a relatively small amount of water can flow at a time. For example, the outflow of an aquarium filter is ideal for this purpose.

Second, it’s good practice to put a filter in front of your UV sterilizer to ensure that the light is passing through relatively clean, high transmittance water. If you have a sump filtration setup, set the UV sterilizer in the last chamber where the water is cleanest.

That said, if cloudy water and low transmittance remain an issue, you need to switch to a high-wattage UV light with a longer dwell time.


How bright your lightbulb will shine is denoted by its power consumption, which is measured in wattage. The higher the bulb wattage, the higher chances of the UV light reaching every nook and cranny of your tank. In other words, the brighter the UV light, the more effective the UV sterilizer will be.

Granted, there’s no concrete rule as to how high the wattage of your UV sterilizer should be, especially since each bulb’s actual light output varies per brand. But in general, the accepted rule is that 4 to 8 watts of light is good for 20 to 40 gallons of water, 20 to 25 watts is good for 20 to 100 gallons, and 40 watts is good for 150 gallons, and so on.

However, some units like the AquaUltraviolet Advantage tend to consume more power while some, like the SunSun JUP-02, are made to be more power-efficient.

Contact Time

The longer the water is in contact with the UV light, the better. This means that if you’re getting models with built-in pumps, you should know the flow rate, as the lower the flow rate, the better. Also, the longer the UV light is on, the more it can kill the microbes in the water. Make sure that your UV light is long-lasting and offers plenty of contact time with water.

Submersible vs. Non-Submersible

UV sterilizers are either submersible or non-submersible. Many aquarists believe that submersible units are safer than non-submersible ones, since even if the unit leaks, the water will stay inside your tank rather than on the floor outside.

The biggest downside, however, is that submersible units tend to look out of place inside an aquarium. Tank keepers who are following a certain aesthetic would likely prefer a non-submersible one that they can hide out of sight.

Other than that though, there’s no reason for you to choose one over the other simply because of this one feature.

Frequently Asked Questions

How Long Does a UV Sterilizer Bulb Last?

This highly depends on a bunch of factors such as build quality and your individual usage, but in general, it’s a good idea to check the efficacy of your bulb every six months or so. If you notice that the light is starting to become weak, that’s a good sign that it needs to be replaced.

Will UV Sterilizers Kill Ich and Other Parasites on My Fish?

Simply using UV sterilizers isn’t enough when dealing with parasitic diseases in fish, as UV light can only kill free-floating microbes and pathogens in the water. If your issue has something to do with ich or other parasite problems in your tank, you need to use some type of medication.

Are UV Sterilizers Safe for My Fish?

It’s understandable why you might be worried about putting an electrical component directly inside your tank.

However, as long as you’re buying quality products like the ones we listed above, there’s nothing to worry about. Even a submerged tube-type will almost always be encased in a waterproof quartz sleeve or have waterproofed quartz bulbs so that water can’t get into the filaments. If you’re experiencing electricity in the water while your UV sterilizer is plugged in, then you have a defective product.

Moreover, UV light itself isn’t harmful to fishes. It kills only free-floating microbes in the water, without any adverse effects on your other tank inhabitants.

Final Thoughts

An aquarium UV sterilizer is a good idea if you want clean, clear, microbe-free water with less hassle. Remember, before you buy your UV sterilizer, make sure to keep in mind your tank dimensions, the capacity that you need, the additional features, and the type that you need to get. Even if there may be a confusing array of different products out there, as long as you follow our buyer’s guide, you should be all set.

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