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Top 5 Best Pond UV Sterilizer of 2020 (Buyer’s Guide)

Owning a pond is an incredibly rewarding experience and can make any garden look stunning. However, to keep your pond looking its best, a fair amount of maintenance is involved. 

Ponds, particularly outdoor koi ponds, are susceptible to algae outbreaks, bacteria, and parasites. This can have a serious effect on the appearance of your pond and the health of your fish. 

A UV sterilizer can help with these potential risks by creating a clean and sterile environment for your fish. The way UV sterilizers work is by using extremely powerful UV light to help eliminate algae, bacteria, parasites, and any other nasties that might be lingering in your water. 

For any pond owner, a UV sterilizer is a piece of equipment you definitely want to have around. It can be a little confusing when it comes to picking a good UV sterilizer for your pond, especially if you’ve never used one before.

To help you figure out the best UV sterilizer for your pond, I’ve reviewed an array of units and taken a close look at their advantages and disadvantages.

After considering all the options our top picks were…

Review Summary

Best All-Rounder

Jebao 36 W Koi Pond UV Light Sterilizer

The unit is 36 watts and has a maximum fluid rate of 4,400 gallons per hour, so it should be plenty for medium-sized ponds.

Jebao 36 W Koi Pond UV Light Sterilizer

Out of all the UV sterilizers I’ve reviewed, this unit is my overall recommendation for most ponds.

For the majority of ponds, the Jebao koi pond UV light sterilizer is a good option. It has an impressive fluid rate of 4,400 GPH and has a wattage of 36. When installed correctly, the unit can remove algae from your water in just 3 to 5 days. It’s also efficient at eradicating other pathogens in your pond water

Best on a Budget

SunSun JUP-01 9W UV Sterilizer

This UV light unit is effective at eradicating bacteria, algae, and parasites from your pond water. It also effectively controls bad odors, which is ideal if you have a particularly bad smell emitting from your koi pond.

SunSun JUP-01 9W UV Sterilizer

This unit is a great choice for pond owners on a budget due to its affordability.

If your koi pond needs an inexpensive UV unit, then you can’t go wrong with one from F

SunSun. It has a water flow rate of 210 gph and a wattage of 9. The device is efficient at eliminating algae, bacteria, bad odors, and parasites without burning a hole in your wallet.

Editor’s Choice

OXYFUL 24 W UV Pond Unit

The unit performs very well and takes care of any algae, parasites, and pathogens in your water. The UV light bulb that comes with the device is very long-lasting and is effective for up to a year, so it shouldn’t need to be replaced very frequently.

OXYFUL 24 W UV Pond Unit

My personal favorite UV device for a pond. It’s a little pricey but is extremely high quality.

Suitable for ponds over 11, 000 gallons, the OXYFUL 24-watt UV light unit quickly kills any pathogens in your water. It does an excellent job at clearing up algae, parasites, etc, from your pond water and making sure your fish are happy and healthy. The UV bulb can last for up to a year, which shows how durable the device is.

What Wattage Should Your UV Unit Have?

The capacity of your pond comes into play when choosing a UV device with an appropriate wattage. Most UV sterilizers are available from 5 watts to 140 watts. Obviously, the bigger your pond, the higher watts you need.

TIP

In general, ponds that hold 500 gallons or less only need 5 to 8 watts. If your 500-gallon pond gets a lot of sun, has lots of plants, and a high amount of fish, then you might need a 10-watt to 20-watt UV sterilizer.

6,000-gallon ponds need a more powerful UV device, with around 40 to 45 watts being sufficient. If a pond this size isn’t shaded and holds a lot of fish and plants, then over 80 watts is advised.

Flow Rate and Turnover Rate

To effectively kill algae and bacteria, your UV unit needs to have a suitable flow rate. The flow rate of your unit is normally measured in gallons per hour (gph) or liters per hour (lph). 

Higher flow rates are usually good for eliminating green water and certain types of bacteria, but a slower flow rate is better for ridding your pond of parasites. For most standard ponds, you should aim for a unit that has a turnover rate of 2 every 24 hours.

Different Colored Koi in Fish Pond
Different Colored Koi in Fish Pond

How Many Gallons Does Your Pond Hold?

If you’re not sure how many gallons your pond holds, then simply multiply the length of it by the width by the average depth to get the total cubic feet. Multiply the total cubic feet by 7.5 to calculate the number of gallons your pond is.

For example, if your rectangular pond is 5 ft in length, 4ft in width, and has an average depth of 6 ft, then the total cubic feet is 120. When you multiply the cubic feet by 7.5, you get 900. This is the total number of gallons your pond holds. 

UV Sterilizer Versus UV Clarifier – Which is Better?

UV sterilizers and UV clarifiers are pretty easy to mix up, but there are a few vital differences between the two types of pond equipment.

UV sterilizers and UV clarifiers are pretty easy to mix up…

While both units use powerful UV lights to kill parasites, bacteria, and algae, UV clarifiers typically have a lower wattage and a higher water flow rate. Like I mentioned earlier, slower flow rates are better for eliminating certain bacteria and parasites as they expose the pathogens to UV light for longer.

Parasites like ich and costia need a longer exposure time to effectively damage them, so a UV clarifier might not be successful for treating these illnesses. 

If you simply want to get rid of unsightly green water from your pond, then a UV clarifier is sufficient. However, if you want to provide your pond with a more sterile environment and want to prevent bacteria and viruses, then UV sterilizers are a better option.

Koi Fish Swimming at the Bottom of the Pond
Koi Fish Swimming at the Bottom of the Pond

Will the UV Light Kill Beneficial Bacteria Too?

Since UV light is efficient at killing bacteria, you might have wondered whether it can also eradicate beneficial bacteria too. Good bacteria is needed in any pond to help with the nitrogen cycle. 

There is a bit of controversy involving UV devices and their effect on beneficial bacteria. For this reason, some pond owners use a UV sterilizer or UV clarifier with low wattage. 

While UV light can kill beneficial bacteria, it is not enough to negatively impact your pond…

While UV light can kill beneficial bacteria, it is not enough to negatively impact your pond. Most good bacteria colonize on filter media, rocks, plants, etc, and UV devices only kill bacteria in the water. 

However, it’s advised to let your pond fully cycle first before you install a UV clarifier or sterilizer to be on the safe side. 

Tips and Safety When Using UV Units

UV clarifiers and sterilizers have very delicate bulbs and glass sleeves, so be careful when you’re assembling the unit or replacing a bulb. The connections need to be secure, but try not to force it as this can cause breakage. 

NOTE

Additionally, when handling the bulb, make sure you don’t use bare hands. The natural oils present on your skin can affect the longevity of the bulb as well as cause it to overheat.

As UV bulbs emit harmful ultraviolet light, it’s crucial that you never look directly at the bulb when it is unshielded. If you need to check the light, only do so through the opaque window on the outer casing, 

How to Install UV Light 

When installing a sterilizer or clarifier, place either one in an area that won’t be easily flooded. Although these types of equipment are waterproof, they should not be submerged.

I recommend positioning the unit on a flat surface that’s dry, such as the lid of a canister filter. Make sure you connect the equipment to a GFI circuit or outlet to prevent electrical shocks.

UV Sterilizers Reviews 

Now that you’ve gotten all the information you need to know about UV devices, you’re probably wondering what the best UV units are for your pond. To help you save time and research, here are some of my top recommendations. Hopefully, these reviews will help you choose the best UV unit for your pond!

Best All-Rounder

Jebao 36 W Koi Pond Light Sterilizer

The unit is 36 watts and has a maximum fluid rate of 4,400 gallons per hour, so it should be plenty for medium-sized ponds.

Jebao 36 W Koi Pond Light Sterilizer

This UV pond sterilizer is my overall recommendation for most ponds as it’s effective and not too costly. The unit is 36 watts and has a maximum fluid rate of 4,400 gallons per hour, so it should be plenty for medium-sized ponds.

Easy Installation

Installing this UV pond sterilizer is fairly easy. It’s best to install the unit after your pond filter, but if you need to use it before the pond filter, make sure you use plenty of pre-filtration. This will help prevent the quartz glass sleeve from breaking due to debris in your water.

As long as you install the unit before your pond filter, it claims to eliminate algae or green water in as little as 3 to 5 days, so it shouldn’t be too long before your pond water is crystal clear again. The unit is also effective at destroying bacteria, viruses, fungi, and parasites. 

The UV bulb is fairly long-lasting and only needs to be replaced after 6 to 12 months of use for optimal performance.

One major drawback of this UV pond sterilizer is its durability. The unit is not made from the most high quality material, which can cause it to break prematurely or leak frequently.

Specs

Pros

  • Simple to install
  • Quickly removes algae
  • Long-lasting light bulb

Cons

  • Not as durable as some other UV pond sterilizers

Best on a Budget

SunSun JUP-01 9W UV Sterilizer

This UV light unit is effective at eradicating bacteria, algae, and parasites from your pond water. It also effectively controls bad odors, which is ideal if you have a particularly bad smell emitting from your koi pond.

SunSun JUP-01 9W UV Sterilizer

If you’re looking for a good-quality UV unit that doesn’t break the bank, then this one from SunSun is a great choice for small ponds. It’s 9 watts and has a water flow rate of 210 gph. 

The device is compact and comes ready to install. No extra tubing or a circulation pump is needed for setup, which makes it easy to get up and run.

This UV light unit is effective at eradicating bacteria, algae, and parasites from your pond water…

This UV light unit is effective at eradicating bacteria, algae, and parasites from your pond water. It also effectively controls bad odors, which is ideal if you have a particularly bad smell emitting from your koi pond.

The unit can be placed vertically or horizontally. It has a built-in pump and includes a UV ballast, UV-C lamp, mechanical pre-filter sponge, and mounting brackets with suction cups. 

However, the design of this device can make it difficult to clean and maintain. Additionally, the unit can break or stop working prematurely as it’s not very durable.

Specs

  • Size: 4” x 4” x 12”
  • Weight: 2 lbs
  • Water Flow Rate: 210 gph
  • Wattage: 9 W

Pros

  • Effectively removes algae and other pathogens
  • Easy to install
  • Compact design

Cons

  • Can be difficult to clean or maintain
  • Not very durable

Editor’s Choice

OXYFUL 24 W UV Pond Unit

The unit performs very well and takes care of any algae, parasites, and pathogens in your water. The UV light bulb that comes with the device is very long-lasting and is effective for up to a year.

OXYFUL 24 W UV Pond Unit

Suitable for indoor and outdoor use, the OXYFUL UV pond unit is a fantastic choice for large ponds. It’s 24 watts and has a fluid rate of 1,320 gph, which makes it suitable for ponds over 11, 000 gallons. 

The unit performs very well and takes care of any algae, parasites, and pathogens in your water…

The unit performs very well and takes care of any algae, parasites, and pathogens in your water. The UV light bulb that comes with the device is very long-lasting and is effective for up to a year, so it shouldn’t need to be replaced very frequently.

Easy Installation

Installing the device isn’t too complicated. It can be placed vertically or horizontally, but is best installed after your filter. 

The reason why I prefer this UV pond unit over the others I’ve reviewed is due to its effectiveness. It quickly clears up your pond water and is great at keeping your pond free of any pathogens. 

However, the device can struggle with extremely large ponds. Despite claiming to be adequate for ponds over 11, 000 gallons, the unit isn’t always effective at sterilizing ponds this big. 

Specs

  • Size: 21.5” x 6” x 5”
  • Weight: 7.5 lbs
  • Fluid Rate: 1, 320 gph
  • Wattage: 24 W

Pros

  • Quickly removes pathogens
  • Easy to install
  • Long-lasting UV bulb

Cons

  • Not always effective at sterilizing large ponds

SunSun CUV-118 18 W UV Lights Unit

This 18-watt UV light device can be used with pumps up to 660 gph, so it’s adequate for ponds up to 5,280 gallons. For the most part, the equipment performs fairly well and adequately removes algae, parasites, and other pathogens from your pond water.

SunSun CUV-118 18 W UV Lights Unit

This 18-watt UV light device can be used with pumps up to 660 gph, so it’s adequate for ponds up to 5,280 gallons. For the most part, the equipment performs fairly well and adequately removes algae, parasites, and other pathogens from your pond water. 

The device isn’t too difficult to install and comes with longer power cords and various hose adaptors. The UV light bulb claims to last for up to 11 months, but it is susceptible to breaking earlier.

My main issue with this unit is its durability. It doesn’t have the longest lifespan and can break down after a few months of use. In addition to this, the device can struggle to sterilize and remove algae from medium-sized or large ponds. 

Specs

  • Size: 12.2” in length
  • Weight: 5.2 lbs (with packaging)
  • Water Flow Rate: 660 gph
  • Wattage: 18 W

Pros

  • Long power cords
  • Comes with various hose adaptors
  • Works adequately for the most part

Cons

  • UV light bulb has a short lifespan
  • Unit is prone to breaking quickly
  • Can struggle to sterilize and remove algae in medium/large ponds

Coralife Turbo Twist 12x UV Pond Device

With a wattage of 36, the Coralife Turbo Twist 12x UV unit is suitable for medium-sized ponds. Due to its twist-flow design, it provides your pond water with ample exposure to UV light.

Coralife Turbo Twist 12x UV Pond Device

With a wattage of 36, the Coralife Turbo Twist 12x UV unit is suitable for medium-sized ponds. Due to its twist-flow design, it provides your pond water with ample exposure to UV light. 

features an indicator light that notifies you when it is actively sterilizing…

The device features an indicator light that notifies you when it is actively sterilizing. It also comes with mounting brackets for hang on or in-line applications, which is handy.

The device is available in smaller sizes, but I recommend using the 12x variety for ponds. This makes sure any algae or pathogens in your pond water are dealt with promptly and efficiently. 

The biggest downfall of this Coralife equipment is its durability. In general, the device has a short lifespan and is prone to leaking and rusting. In addition to this, the bracket included with the device is poor quality and can snap easily.

Specs

  • Size: 20.9” x 3.9” x 5.6”
  • Weight: 7.25 lbs
  • Fluid Rate: Unknown
  • Wattage: 36 W

Pros

  • Unique design provides your pond water with ample UV exposure
  • Indicator light lets you know when the unit is operating
  • Comes with mounting brackets

Cons

  • Short lifespan
  • Prone to rusting and breaking
  • Mounting brackets are not very durable

Conclusion

After considering all the options our top picks were…

Best All-Rounder

After looking at a variety of products, I think the best UV unit is the Jebao 36 W Koi Pond Sterilizer. It’s 36 watts and has a water rate of 4,400 gph. It promptly and efficiently removes algae and other pathogens from your water.

The feature I like the most about this device is just how quickly it gets to work. When installed correctly, any algae in your water is taken care of within 3 to 5 days. This means you don’t have to wait very long for crystal clear water.

The only downside with the unit is its durability. Unfortunately, the material of the device is not the best quality. This can cause the equipment to leak or break easily. However, on the plus side, the bulb included with the device can last up to 6 to 12 months, which is quite a long time!

Other Options

If the Jebao sterilizer doesn’t appeal to you, then two other best UV pond units are the SunSun JUP-01 9W UV Sterilizer and OXYFUL 24 W UV Pond Unit. 

Best on a Budget

The former is a fantastic option if you’re on a budget. It effectively rids your pond water of algae and other pathogens. It’s very easy to install as it comes with a built-in pump, but it can be hard to clean due to its design. Additionally, the device can wear out quickly.

Editor’s Choice

OXYFUL’s UV pond device is a little pricey, but is incredibly effective at sterilizing your pond water. It easily removes algae, parasites, bad odors, etc, from your pond water. The light bulb that comes with the equipment is also very long-lasting. Unfortunately, the device can struggle to sterilize the water of extremely large ponds, despite claiming to be suitable for ponds over 11, 000 gallons.

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