Aquarium Ultraviolet Sterilizers - Underwater Eco Systems

Aquarium Ultraviolet Sterilizers

Aquarium Ultraviolet Sterilizers
High intensity ultraviolet light destroys the DNA in living cells and can be an effective means to control living pathogens. The most effective UV light is the high energy UV(C) light roughly at the wavelength of 250 Angstroms. To be effective, UV Sterilization (UVS) must expose the pathogens to high enough light intensity for a long enough period of time. Most professionals cite 35,000 to 100,000 microwatts per second per square centimeter as the norm, which works out to roughly 10 to 25 gallons per hour per watt (or less for units not operating at peak efficiency).
 
Common problems which can reduce efficiency and kill rate are:

• Allowing the water to flow too fast past the UV light.
• Light blockage due to a build up of salt deposits or bacterial slime on the bulb.
• Fading of the light due to age of the bulb (which typically have a six month life.)

The same property of this light that kills germs can damage your eyes, and special care MUST BE TAKEN to avoid direct or indirect eye contact with this light. This is especially serious because the damage occurs inside your eyes before you feel any pain. Too many people have already damaged their eyes in this way!

The UV(C) light does not penetrate water very well, so to be effective, UV Sterilizers commonly position the UV bulb close to the water which also can pose a risk of electrical shock should the bulb break.

There are three types of Aquarium UV Sterilizers:

Tray type. (Typically homemade) with UV bulbs suspended in a reflecting fixture over a shallow tray of slow flowing water. Benefits: easily cleaned, can be cheap, can be made large enough for commercial applications. Problems: safety risks to your eyes, too large and awkward for many home Aquarium uses.

Tube type, wet bulb. Tube types have the benefit of exposing all sides of the UV tube to water with no reflector. The water passes directly past the bulb which is mounted in a waterproof tube. Benefits: cheap, compact and effective. Problems: difficult to clean the slime accumulations from the bulb, safety risks due to electrical shock.

Tube type, dry bulb. Similar to above, but the Aquarium UV tube is surrounded by a quartz tube insulating it from the water. These are more expensive and probably safer. Changing the light bulb is easier and dry bulb tube types can have a internal device to wipe slime from the quartz tube. Some of these types come with sensors to monitor the intensity of the light to let you know when to replace/clean the bulb.