UV SterilizerUltraviolet (UV) sterilization is an effective and underutilized method of filtration for aquarium systems.

Algae, parasites and bacteria can wreak havoc within the aquarium environment. Using a UV sterilizer helps reduce the risks posed by these common aquarium nuisances.

Choosing a UV sterilizer may seem daunting. Our goal with this article is to explain how UV sterilizers work, how to select an appropriate unit for your aquarium and how to set one up once you’ve made your purchase.

UV sterilization is in fact a very simple process for removing unwanted water borne bacteria, parasitic, fungal, viral, algae and other unfriendly pathogens out of aquarium water by exposing it to high intensity UV light.

UV SterilizerFreshwater aquariums and ponds are easier for UV rays to penetrate and sterilize compared to their saltwater counterparts. This is an important tidbit to remember when shopping for a UV sterilizer; manufacturer recommendations are often geared toward freshwater aquarium and pond applications. If you have trouble applying the manufacturer’s recommendations for water volume to your aquarium system feel free to contact us. We’re here to help.

Flow rate is also important in UV sterilization. Slower flow means longer contact time under UV light. The longer the exposure, the greater the rate of sterilization. Algae and bacteria, for example, can be killed with minimal sterilization. Higher levels of UV light are required to eliminate parasites.

Multiple flow rate recommendations are often provided for a single UV sterilizer. These recommendations are based on an aquarist’s desire for clarity (algae/bacteria) or complete sterilization (parasites/viruses).

Although this chart only pertains to Aqua UV brand sterilizers, it is an excellent reference for flow rate and tank size recommendations.

Marine aquarium hobbyists debate the need for UV sterilizers since they can have a negative effect on the beneficial bacteria in an aquarium system. These differences of opinion usually only involve marine and reef tanks with live rock. Proponents reinforce the benefits of UV sterilization, such as disease and algae prevention.

You’ll have a few options for plumbing your UV sterilizer once you’ve chosen a model appropriate for your tank size and desired rate of sterilization.

UV SterilizerMost sterilizers are designed for external use and require a separate water pump to provide sufficient flow. You may use a dedicated pump to pump water from your aquarium or sump through the sterilizer and back into your aquarium/sump. You can also plumb the unit inline with your return or chiller pump. Just make sure you’re using the correct sized pump.

Some UV sterilizers are submersible. You may even find some smaller models with built-in pumps. It is typically best to have the UV sterilizer setup as your last method of filtration after the mechanical and biological filters.

The following steps outline how to install an external UV sterilizer on a home aquarium.

These steps still apply if you are installing a submersible UV sterilizer. Just remember the unit you will be using will actually be underwater. If you opt for a smaller unit with a built-in pump, just place the UV sterilizer inside your aquarium or sump and plug it in. If you’re installing your UV sterilizer outside for a pond or water fountain, the same basic principles apply. Just make sure the unit you’ve chosen is rated for outdoor use.

Without further ado, here is how to install an ultraviolet (UV) sterilizer:

  1. First and foremost, read through the entire product manual. Note any precautions or safety guidelines. Use an appropriately sized pump to provide the necessary flow rate. Make sure you’ve got your essential plumbing parts, namely tubing and elbows. If you get stuck on a single step or need helping choose a UV sterilizer and plumbing parts, remember: we are here to help you!
  2. Next, find an appropriate place to mount your sterilizer. Some units hang from your aquarium. Others are easily mounted below your tank on or inside the stand.
  3. Cut your vinyl tubing or PVC to accommodate the distance to and from your UV sterilizer. Some units are labeled with an inlet/outlet. Take note before cutting your tubing.
  4. Connect the tubing/PVC to your pump then attach to the UV sterilizer. Most sterilizers come with tubing connections. Just be certain you have all the necessary parts before installing the unit. The pump needs to be plumbed inline before the sterilizer and push water through the unit then back into your aquarium. When the water returns back to your tank or sump, you can use a simple U-tube to make an easy fail-safe connection back to the aquarium or sump. Use hose clamps when using vinyl tubing and, if using PVC, wait 24 hours for any glue to set and dry before running water. Teflon tape should always be used for any threaded parts.
  5. Now install the fragile lamp and quartz sleeve. Do not touch the quartz sleeve or lamp with your fingers. The natural oils in your skin can negatively affect the glass components. Use cotton gloves or a paper towel to avoid direct contact with the glass. Tighten the fittings as necessary to get a water-tight seal. Attach the power supply to your bulb as directed but do not plug in the unit.
  6. Once your plumbing is in place and the pump is connected, proceed to water test for any leaks. Simply plug in the pump and let it run for a few minutes so you can watch for leaks. If no leaks are found and the ground is dry, you may now plug in the bulb.

Congratulations! You have successfully installed a UV sterilizer.

Replace your UV lamp every 6-12 months. If you wait longer, your bulbs will no longer emit the UV rays required to properly sterilize aquarium water.

Keep your quartz sleeve free of debris or build up. A dirty quartz sleeve can block the UV rays and render your sterilizer useless. Just remove the quartz sleeve and wipe it clean every time you change out your bulbs. Always remember to clean and maintain your pump to ensure proper flow rate through your sterilizer at all times.