A UV sterilizer emits ultraviolet light rays into your aquarium water which can effectively damage the DNA of harmful bacteria, parasites, and algae which then reduces the proliferation of these pests in your aquarium. When set up correctly an Ultraviolet Sterilizer can improve water clarity, slow the spread of algae, reduce dinoflagellates, and prevent outbreaks of disease and parasites.
The challenge for many hobbyists is understanding how to install and use the UV sterilizer correctly and achieve the most effective sterilization because if you're not doing it right, the benefits are negligible at best.
While UV sterilization for aquariums has been around for quite some time, it is only been the last 10-20 years or so that reef hobbyists have adopted this method. Early skepticism revolved around the fact that UV sterilizers were thought to disrupt the biodiversity and natural food chain that was critical to reef aquariums but this has been proven wrong time and time again. The reality is that you can have an incredibly biodiverse reef aquarium with a healthy biological filter and still run a UV sterilizer.
The way it works is quite simple, aquarium water is pumped through a chamber that contains ultraviolet light. The ultraviolet rays damage the DNA of living organisms that are suspended in the water making it impossible for those organisms to reproduce. This can effectively keep the population of harmful pathogens and algae to a minimum and, therefore, reduce or eliminate the effects of those pathogens in your aquarium.
In order for the UV sterilizer to be effective, the pathogens must be suspended in the water and pass through the UV with sufficient exposure to ultraviolet light.
Different organisms can tolerate different levels of UV exposure which is why we adjust the flow rate to target specific types of organisms. The slower the flow, the longer the exposure to UV light rays. Then again, if you go too slow, some pathogens can reproduce faster than you can sterilize them so it's a balance. Finding that flow balance to target specific pathogens is the key to success.
For the most part, you can choose one of two different flow rates as recommended by the manufacturer when tuning your sterilizer. See the specifications above for the Pentair 40 Watt UV. The higher flow rates are used to target bacteria and algae while the slower flow rates are used to target protozoa (disease-causing parasites).
UV sterilizers can be applied all the time or just periodically to address a problem. When used correctly, they can help overcome things like dinoflagellates and slow down the spread of algae. You might also use a UV when stocking the aquarium to help reduce the chances of disease. Some hobbyists choose to run them 24/7 while others choose to run them on a timer for only a portion of the day. Some folks just keep a UV on hand and will only use it when something comes up, the Aqua UV Advantage hang-on sterilizer is great for this just because it's small and can hang right on your display.
The most important thing to remember about UV sterilizers is they are not killing pathogens or eliminating them completely but rather reducing the free-floating population in your aquarium which then reduces the negative effects. Anything that doesn't suspend into the water column will not be harmed including beneficial bacteria.
UV Sterilizers are rated via wattage. Larger tanks require higher wattage UV sterilizers and simply use the manufacturer's recommended tank ranges. Be mindful of the UV sterilizer's physical size and where you need to mount it; they can be cumbersome and awkward to mount inside your tank stand.
Choose a pump that can supply the recommended flow rates outlined by the manufacturer, be mindful of any head pressure that will be created via the plumbing, and always install a valve so you can control that flow rate. Controllable DC pumps will work just as well for controlling the flow but the most important thing is to ensure you can achieve the recommended flow ranges for your UV sterilizer.
Most UV sterilizers will not include a pump or any of the required plumbing so you will likely need some tubing, hose clamps, and possibly some plumbing fittings to get the job done. The exact fittings and tubing would be based on the particular specifications of the UV sterilizer you choose and it is best to simply adapt to the tubing size of the pump.
Find a suitable location to mount your sterilizer within close proximity to your sump or aquarium. When mounted horizontally, the inlet and outlet should be facing upwards to avoid trapping air. When mounted vertically, the water should enter through the bottom and exit through the top of the UV sterilizer for the same reason. Trapped air can heat up and reduces the effectiveness of the sterilizer. Most UV sterilizers can be mounted on the wall using specialized brackets or PVC clamps.
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A separate pump is used to push water through the UV sterilizer and it is best to use a dedicated pump to have absolute control over the flow-through rate.
You need to set up the UV sterilizer in such a way that prevents recycling, pull water from chamber A and return that water to Chamber B or C downstream. If water is returned from the UV into the same chamber it is fed from, it will recycle the same water and reduce the effectiveness of the UV.
Aqua UV makes the Advantage HOB UV Sterilizers which are designed for hang-on your display and are suitable for tanks up to 75 gallons. These work out great for smaller aquariums or situations where you don't want to plumb a full-size UV and are incredibly easy to set up.
Flexible tubing is the easiest route to connect the pump but PVC is also suitable. Reference the inlet/outlet connection size of your UV sterilizer and then adapt that to fit the tubing size of your pump. Use hose clamps to prevent links and secure the return tubing in such a way that it is not at risk of falling out of the tank/sump when running.
Installing the UV lamp is easy, be sure the UV sterilizer is not plugged into the wall and unscrew the compression cap on the end. Plug in the lamp/bulb using the 4-pin connector and take care not to touch the glass on the bulb directly with your fingers, wear gloves or use a towel when handling the bulb. Do not apply power until water is moving through the UV to avoid heat build-up and damage to the UV.
Finally, it's time to turn on the pump and dial in the flow. Flow rate is critical and choosing the right pump can get you into the ballpark. That said, measuring the flow is the only way to know for certain and there is just a couple of ways you can do that. We also highly recommend the video linked at the bottom of the page for more detailed tuning instructions.
The two most hated things for a saltwater aquarium keeper are fish diseases and &#;bad&#; algae. Some hobbyists make an attempt to go all out against these threats by using an ultraviolet sterilizer. At least in some cases, a properly sized and properly installed sterilizer unit can indeed help to reduce the incidence of disease or algal blooms. However, they are never foolproof. And, even more notably, their use does not come without a price.
Here we examine the limited benefits UV sterilization as well as some of the drawbacks. We shall begin by describing how UV sterilizers work.
Germicidal ultraviolet radiation kills microorganisms in two different ways. In the first, it disrupts the organism&#;s genetic material (DNA), thereby outfight killing it or rendering it incapable of reproducing. In the second, when applied to aqueous environments (e.g. aquariums), it generates toxic oxidants that degrade the organism&#;s vital organelles (cell membrane, chromosomes, etc.).
When it comes to a particular UV sterilizer unit&#;s killing efficiency, exposure is everything. Much more intense and prolonged exposure is required to kill larger organisms. Thus, UV is by far most lethal towards microorganisms (i.e. bacteria and archaea) and extremely tiny algae such as Nannochloropsis. Lethality for a comparatively large and well protected diatom such as Thalassiosira is considerably lower. Only the most intense UV light and longest exposure times are capable of killing the &#;huge&#; cells of parasitic protozoans such as Cryptocaryon.
One additional factor in the overall effectiveness of a UV sterilizer is the spectral output of its bulb. Some wavelengths within the ultraviolet range are more lethal than others. The UV range is divided into UV-A, UV-B and UV-C. UV-A (320-400 nm) is least effective; however, when emitted from some aquarium lights, it can cause burning of corals by harming zooxanthellae. UV-B (280-320 nm) is perhaps a bit more destructive to living tissues, but still isn&#;t all that lethal to most organisms. UV-C (200-280 nm) is certainly the most deadly to small lifeforms and is the wavelength most frequently encountered in UV sterilizers. Specifically, most sterilizer bulbs emit wavelengths of around 254 nm.
Where you plumb your unit matters. Some aquarists like to conceal the unit within the cabinetry, running it so that it draws water from, and empties back into, the sump. However, this reduces the unit&#;s efficiency (especially in systems with smaller sumps or low system turnover rates) because it essentially keeps redrawing the same water over and over again. Only slightly better is plumbing the unit inline to your main filter system, just before water is returned to the display tank. The ideal is to draw water into the sterilizer from the sump and return it directly into the display. This not only prevents re-recirculating the same water, but it also makes cleaning, bulb changing and fine-tuning the flow rate a lot easier.
The killing efficiency of a given UV sterilizer unit at a given time depends upon several factors. These include:
Quite often, for UV sterilization to be very effective (especially against fish parasites), the aquarist must obtain a substantially &#;oversized&#; unit. If you really want your next unit to kill stuff, be sure to read the ratings on each box very carefully as you shop. Remember that ratings for saltwater applications are significantly lower than those for freshwater applications.
Many manufacturers provide two sets of ratings: One for &#;clarification&#; and another for &#;sterilization.&#; Clarification means that at a given flow rate, the unit is capable of killing water-coloring microbes and microalgae only; true sterilization implies that even with all things considered (average water turbidity, average distance of target organism from the bulb, etc.), the unit can kill most common protozoa.
There are some disadvantages to using Ultraviolet sterilization over other types of sterilization. For example, whereas ozone sterilization is effective throughout a larger treatment zone (reactor, skimmer, sump, etc.), UV sterilization can only kill those organisms that pass right through the unit. Thus, nuisance benthic (filamentous or film) algae can spread without interruption. Similarly, some parasites can drop their eggs onto the aquarium substrate where they may develop without harm.
Frankly, there are also some clear disadvantages to using any kind of sterilization. The biggest downside is loss of beneficial plankton. Think about it&#; Killing our phytoplankton and bacterioplankton have two undesirable results. The first reason is that without these primary producers, your nitrate and phosphate levels can go out of whack (usually toward excess). Yes, whether you carbon dose or not, these organisms sequester significant quantities of nutrients! The other reason is that these tiny plankton are a natural and hugely important source of nutrition for many filter-feeders including corals. And most reef aquaria already suffer from a lack of plankton to begin with!
None of this is to say that UV sterilizers are inherently bad. For example, they very effectively help to prevent the spread of disease when used in quarantine systems. You should, however, be aware that sterilization unavoidably presents some sacrifices. Thus, in our opinion, if you have issues with bad algae or with disease, improving your husbandry/maintenance practices should always be the first resort!
Are you interested in learning more about wholesale uv sterilization device? Contact us today to secure an expert consultation!