Uv Sterilizer (which One)?

UV Sterilizers: Which one is right for you?

Microscopic organisms can be one of your aquarium's worst enemies. A UV sterilizer is a great way to help protect both current aquarium inhabitants and new additions from the health risks presented by bacteria and parasites. UV sterilizers use a special fluorescent UV lamp that produces light at a wavelength of 253.7 nanometers. Aquarium water is pumped past the lamp at a low flow rate and is essentially "irradiated," controlling free-floating bacteria, algae and parasites.

When choosing a UV sterilizer, ask yourself the following questions:

-What kind of organisms do I wish to control? Bacteria, parasites, or both?
-What is the proper flow rate required to accomplish my goals?
-Do I want an in-line or hang-on unit?
-Differences in UV Sterilizers

UV sterilizers differ in a number of ways. The first is their position in the water flow- either in-line or hang-on. In-line models are plumbed into the system after the mechanical filtration unit, as the last filter in line before water returns to the aquarium. You may need to use a ball valve or a "T" connector in your return line to slow down the flow rate going to the UV sterilizer.

-Tips from the Techs
Always locate UV filters after mechanical filtration to help slow buildup on the quartz sleeve, thus requiring less maintenance in the long run.

Hang-on models are mounted on the back of the aquarium and are usually fed by a submerged power head or a return line from a canister filter. These models are easier to install and somewhat easier to maintain.

Another difference is the use of quartz glass sleeves. Some models feature a quartz sleeve, which increases the brightness and effectiveness of the unit. Some models claim that their designs results in a longer "dwell time," which may enhance effectiveness as well.

-Choosing the Right Size Unit

For proper use, the UV sterilizer must be matched to the proper flow rate to ensure an efficient "kill dose" for the organisms you wish to eliminate. A slower flow rate is required for controlling parasites, as they are more resistant to irradiation than are bacteria.

UV Bulb(Watts)/To ControlBacteria and Algae(gph)/To ControlParasites(gph)
4 60 N/A
8 120 N/A
15 230 75
18 300 100
25 475 150
30 525 175
40 940 300
65 1700 570
80 1885 625
120 3200 900
130 3400 1140

The chart provides guidelines for determining the bulb size and flow rate you require for UV sterilization. To use this chart, identify the maximum GPH rating in either column that most closely matches the number of gallons in your aquarium. The maximum flow rate should be greater than the number of gallons in the system (tank & sump).

For example, if you have a 100 gallon tank and want to control parasites, you would need a minimum 18 W UV with a maximum flow rate of 100 GPH. A 25 W UV at a flow rate of 150 GPH would be preferable. With UV sterilizers, bigger is better.

-Operating Guidelines
While UV sterilizers usually do no harm, do not use one when you first cycle your aquarium, as it may kill beneficial bacteria before they attach to the bio-media or gravel. Also, many medications can be "denatured" by the UV light, so the sterilizer should be turned off when using medications, especially chelated copper treatments. The UV light will "break" the bond of the chelating agent, and the aquarium will have a sudden, lethal concentration of ionic copper.

Once you introduce a UV Sterilizer into your system, carefully monitor your aquarium's temperature. Depending on your aquarium size and flow rate, a UV Sterilizer may add heat to your aquarium water. If this occurs, you may wish to consider installing a chiller.

-Maintenance Requirements

As with all sophisticated pieces of equipment, your UV Sterilizer needs to be properly maintained to remain effective. Quartz sleeves should be cleaned at least every six months. UV bulbs will need to be replaced after 9 to 12 months of continuous use.

UV sterilizers have many advantages and very few drawbacks. In addition to being easy to install, requiring low maintenance, and being affordable, they can provide huge health benefits for your fish. Make sure you get one that is the correct size, operate it under the appropriate conditions, and follow the manufacturer's maintenance guidelines to ensure that your UV sterilizer can do the job it was designed for.