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To earn the BRS Recommended badge of approval the aquarium product must offer great value at its particular price or accomplish something truly unique for your aquarium. In many cases, it is a combination of both that brings these products to the forefront and worthy of highlighting.


The Pentair UV Sterilizers are the only large format UV sterilizers we choose to stock here at BRS and earned the BRS Recommended seal of approval by being the BEST sterilizer for the money. The are not only highly effective and built with excellent quality but are also easy to use and install on home aquariums.


Pentair Aquatic EcoSystems Website


Pentair is a global thought leader in everything water including industrial water purification, household drinking water, aquaculture, disinfection and aquarium filtration equipment. They are not making inexpensive hobby grade gear either, they manufacture high quality equipment for a wide range of industries and applications.


For reef tanks, when used correctly a Pentair UV will control the spread and outbreak of pesky algal and bacterial blooms, cyanobacteria, and dinoflagellates. They are also a very effective tools for protecting fish from a myriad of common diseases and parasites.


In addition to performing the task at hand very well, Pentair provides very realistic sizing recommendations and performance expectations ultimately making it easy for you to choose the right UV.


UV specifications and flow rates


How to choose the right UV

Choosing the right UV is easy based on guidance from Pentair and we have clear ratings on the BRS site for the right wattage per tank size. The two most common sizes being the 25 watt (up to 130 gallons) and the 40 watt (up to 260 gallons).


There really is no need to go bigger than suggested to achieve the desired results but there is no harm in it either. The important thing to remember is never go lower than the suggested wattage for your tank size or else it won’t work.


Why does flow rate matter?

After getting the wattage right for your tank size, you want to next consider the flow through rate which is critical to getting the desired results out of the UV sterilizer.


The amount of water flow controls how long the water dwells inside the UV typically called contact time and also how many times per day your tank water passes through the unit. Higher flow = less contact time and more frequent pass through and vice versa. The contact time and pass through rate are important for the intended purpose of the UV on your aquarium and flow rates are clearly outlined on our website.


UV sterilizer on sump


For example, let’s consider a 25 watt UV on a 120 gallon aquarium. In order to protect your fish from diseases and parasites, you will need to accomplish 79 - 131 GPH. In order to prevent the spread of bacterial blooms, cyanobacteria, dinoflagellates and many of the common nuisance algae species you want a much faster flow through rate at 472 - 788 GPH.


The reason is because the necessary contact time to kill off bacteria and algae is far less than what is required to kill of diseases and parasites. Furthermore, the more frequent pass through at higher flow rates is optimized for organisms with a faster reproductive cycle such as bacteria and algae.


Color of water comparison


Water clarity comes into play here as well because with clean and clear water it is easier for the UV light to pass through. Therefore, if you are running a regular dose of activated carbon and maintain clear water 99% of the time, you can shoot for the higher end of the flow range. In situations with dirtier water that contain yellow pigments, it is wise to shoot for the lower end of the flow range to help get the necessary contact time for effective sterilization.


Pentair UV types


Can I set up my UV sterilizer to both protect my fish against diseases and stop algae?

The answer is NO, you really need to pick one objective and dial the flow appropriately. Slower flows will not be able to keep up with the fast life cycle of algae and bacteria and the higher flow rates will simply not allow for sufficient contact time effectively kill parasites and protozoa that infect your fish.


Having said that, you can choose a drastically larger wattage or High Output type UV sterilization system which will then allow for the faster flow through and still be strong enough to stop the spread of disease.


For most reef hobbyists, the primary goal is going to be avoiding the ugly cloudy water, nuisance algae and unsightly slime that is common with new and/or neglected systems which means most will go the way of higher flow rates through a single appropriately sized UV sterilizer.


UV sterilizer quartz sleeve and bulb


Don’t forget to replace your bulb!

Pentair makes these very accurate recommendations based on the performance of the bulb towards the end of its life. This way you can expect the UV to perform as intended throughout the entire 9,000 hours or one year of use that is recommended per bulb.


UV Sterilizer on BRS Lab Tank


End of story, the Pentair UV sterilizers come with clear and direct guidance to make your life easy and you can rely on them to get the job done when used correctly. This is why they are BRS Recommended.


There are a couple more things to consider before diving in and buying a UV for your reef tank we want to share. First and foremost is they work best when used as a preventative measure, not after an outbreak has occurred. You can install them after the fact and they will help but this is one of the situations in which an ounce of prevention is worth a pound of cure. Install a UV sterilizer on day one for the best results. Last but not least, UV sterilizers are big simply based on how they work. Be sure to check out dimensions and ensure you have a solid plan for mounting and installation under or around your tank. For more information, you can visit the product descriptions on our website or check out the Pentair UV data sheets.