UV Sterilization Selection Guide

Drs. Foster & Smith Educational Staff

How do I choose a UV sterilizer?

Choosing the Right Size Unit

The chart below 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 will need a minimum 18 watt UV with a maximum flow rate of 100 gph. A 25 watt UV at a flow rate of 150 gph would be preferable. With UV sterilizers, bigger is better.

Maximum Flow Rate for Controlling:
UV Bulb (Watts)	Bacteria and Algae	Parasites	Aquarium Size
8	120 gph	N/A	under 75 gallons
15	230 gph	75 gph	75 gallons
18	300 gph	100 gph	100 gallons
25	475 gph	150 gph	150 gallons
30	525 gph	175 gph	175 gallons
40	940 gph	300 gph	300 gallons
65	1700 gph	570 gph	570 gallons
80	1885 gph	625 gph	625 gallons
120	3200 gph	900 gph	900 gallons
130	3400 gph	1140 gph	1140 gallons

UV sterilizer while cycling my aquarium?

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.

How do you maintain a UV sterilizer?

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.

Is a UV sterilizer worth it?

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 for which it was designed.