If you’re looking for a way to eliminate harmful bacteria, viruses, or parasites from your fish tank, you might want to consider a UV sterilizer. A lot of aquarists swear by them for these reasons, and they can even help get algae blooms under control.
Let’s take a look at everything you need to know about UV sterilizers to help you determine whether or not you need one for your tank.
Table of Contents
What is a UV Sterilizer for Aquarium?
First, let’s talk a little bit about UV light. You might be thinking that this UV light is the same type that we wear sunglasses and sunscreen to protect ourselves against, but that’s not exactly true.
UV light does come from the sun, but only UVA and UVB light make it through the atmosphere. These are the two types of UV light that are known to cause sunburn, age spots, eye damage, and skin cancer.
But this is not the same type of UV light that these aquarium sterilizers use. The sun also puts out UVC light, but the wavelengths are so short that UVC light can’t make it through the Earth’s atmosphere.
But, scientists figured out a way to produce it from a lightbulb, which is what UV sterilizers use. We’ll mention this a few times because it’s important, but UVC light doesn’t kill organisms. It mutates them so they are unable to grow and reproduce.
A UV sterilizer is another way to help keep your tank clean and make sure the water is healthy for your fish. As you probably already know, your fish don’t do well in dirty water. Unfortunately, the tank filter isn’t always enough.
Filters are great for mechanical filtration, that is, removing large pieces of debris, like pieces of dead leaves and other detritus. But no aquarium filter can get rid of all the microorganisms floating around inside your tank.
UV sterilizers help control the growth of bacteria, viruses, and parasites that your regular filter cannot. They come in a range of shapes and sizes so, no matter how small or big your tank is, you’ll find a UV sterilizer that fits.
How Does a UV Sterilizer Work in an Aquarium?
The short answer is that a UV sterilizer exposes the microscopic bacteria and other living things in your aquarium water to UVC light. UVC light damages the DNA, which creates a mutation, preventing the organism from being able to reproduce or grow.
A UV sterilizer integrates into your regular filtration system. Ideally, you should set it up so the water travels into your filter’s intake and through the filter media before entering the UV sterilizer.
The UV sterilizer works by exposing the water to UVC light. While you might be picturing a bright blue light similar to what you may have seen in a tanning bed, in most cases, a UV sterilizer’s light is enclosed in a durable housing. You don’t see it, and nothing else in your tank is exposed to it.
As the water travels through, exposure to the UVC light sterilizes the water, getting rid of algae, bacteria, parasites, and viruses by disrupting their DNA. Again, this only happens to free-floating microorganisms that circulate through the filtration system. Your fish and other plants and animals in the tank are safe.
Pros and Cons of UV Sterilizer in Aquarium
If you’re considering whether you need a UV sterilizer in your tank, take a look at this list of pros and cons to help you decide.
Pros:
- UV sterilizers only kill free-floating organisms, so the beneficial bacteria in your substrate and filter media are not affected.
- They can help control difficult algae blooms.
- UV sterilizers are somewhat effective against ich.
- Most UV sterilizers connect right to your filtration system, but there are free-standing options available.
- Different flow rates target different organisms so you can customize them to the needs of your tank.
Cons:
- A UV sterilizer will not make up for a poorly maintained tank.
- They only work when installed correctly and running at the right flow rate.
- UV sterilizers will not cure any diseases your fish may already have from bacteria, parasites, and viruses in the tank. They can only prevent future infections.
- They are expensive.
Do You Really Need to Use a UV Sterilizer?
With all of the benefits of a UV sterilizer, you might be wondering if you really need one. Maybe you know a lot of people with aquariums and no one has ever mentioned one or the guy at your local fish store has never recommended it to you, so you’re not sure.
So, do you really need to use a UV sterilizer?
No, you don’t necessarily need to use one, but they are very effective and they do have their place.
If you have a tank that you maintain meticulously, with regular water changes and weekly testing, you might not benefit from a UV sterilizer.
But, let’s face it, sometimes problems occur in an aquarium that are out of your control. Say you buy a new fish or plant, add it to your tank, and all of the sudden, your otherwise pristine tank gets cloudy.
The point is, yes, you may get lucky and go for a very long time without any incidents. But things happen, so it’s a good idea to know when a UV sterilizer can help you with your problems.
Who should get a UV sterilizer? If you frequently get cloudy water from bacteria or if you have regular algae blooms that are hard to get under control, a UV sterilizer is a good investment.
But do you really need to use one? Maybe not. It’s possible to get issues in your tank under control without one. But why wouldn’t you want all the help you can get?
One thing to remember is that a UV sterilizer is not magic. Putting one in your tank will certainly help keep things under control, but it isn’t an excuse to stop performing regular maintenance.
UV light has to be able to penetrate the water to get to the organisms. The cleaner the water, the better it can do its job. That means that you still have to do regular water changes and test your water to make sure things stay healthy and balanced.
Conclusion
UV sterilizers certainly have their place. There’s no better way to safely manage the microscopic parasites, viruses, and bacteria that may be floating around in your aquarium. One of the best things about them is that they can take care of these harmful invaders without affecting the health of your plants and fish.
But if you choose to invest in a UV sterilizer, remember, it’s not a substitute for good tank maintenance. You still have to do regular testing and water changes to make sure your tank stays healthy and balanced.
Another thing to keep in mind is that UV filters are preventative. They’re not a cure. If your fish are already sick, you must make sure you treat the water so that the fish get the medicine they need.
A UV sterilizer can help prevent problems in the future, but it will not cure something that is already affecting your fish.
I have a 125 gallon tank with a terrible case of brown algae. I only have 4 fish, 2 large Orandas, and 2 small Orandas. Any pleco I’ve added to the tank die. I change 60% of the water every two weeks. I only feed the fish once a day, and very little. The water itself is crystal clear but brown algae covers the mopani wood, faux plants and the glass in some places. I’ve had a friend who owns an aquarium maintenance company come look at the tank. He ran his own tests and said he has no idea what’s causing the problem or how to get rid of it. I have 2 Eheim Pro 4+ filters, 2 dual air pumps, and 2 heaters going. The filters were last cleaned in October. At that time I took everything out of the tank, cloroxed the daylights out of them, scrubbed the glass, and drained all the water except for enough for the largest fish. I use PhosGuard in the filters. I’m out of ideas except to ask about a simple to set-up UV system for my tank. Do you think it would do the trick? I used to have a 75 gallon tank in my all seasons room. It sat in direct, bright sunlight year round, I never had an algae problem with it. When it sprang a leak, I replaced the tank with the 125, which sits in my livingroom where it doesn’t get any sunlight, only the lights on the hood. I’m seriously considering moving the tank to the all seasons room but I would lose the enjoyment of seeing the fish. Any ideas? I greatly appreciate it. Also, I signed up for your forum, but I couldn’t find where to login. Thanks again.
For what it’s worth, I had a similar problem. I moved everyone to another tank and changed my substrate and installed a UVC filter. Problem gone. I’ve since removed the UB filter and the tank looks good. I have Platties, Pleco’s and Mystery & Nerite snails. The tank is heavily planted.
Good Luck!