» Posted by on Aug 28, 2014 in Blog, Christin D, Education, Freshwater Fish, Reef Aquariums | Comments Off on Custom Aquarium Advice: Ultraviolet Sterilization

Custom Aquarium Advice:
Ultraviolet Sterilization


By Christin Delahay

When considering an equipment purchase for a home custom aquarium, we as consumers typically have a mental list of what we need: Tank (of course), filter of some sort, heater, and thermometer… When we begin considering a marine ecosystem, we know we need different stuff too – a wet/dry or a sump, pumps, valves, a protein skimmer. We often forget one of the most important aspects of maintaining a healthy, disease free system – the unsung hero of the custom marine aquarium: the Ultraviolet Sterilizer.

Ultraviolet sterilization, (U.V.) is arguably one of the most effective methods of eliminating bacteria, algae spores and parasites. It requires no chemicals, is reef safe, and helps keep your marine ornamentals in peak physical health. If someone told you that you could avoid the dreaded “Ich” with one simple piece of equipment, you would certainly listen up, wouldn’t you? Ultraviolet sterilization is a very effective means of eliminating free-swimming Cryptocaryon irritans, and Amlyoodinium oceelatum, ectoparasites that are the most common scourge of the captive marine ecosystem.

Custom Aquarium Advice: Ultraviolet Sterilization

A U.V. works by irradiating particles that pass near the light. This process is harmless to your system (well, to your INTENDED inhabitants!) because this irradiation takes place in a light-tight tube inside which lies the ultraviolet light bulb. A pump carries water out of your tank, through the U.V. chamber and then returns it to your tank. It is very important to note that the key to effective ultraviolet sterilization is FLOW RATE. The rate at which water flows past the ultraviolet bulb, allowing dwell time, is the critical part to properly running a U.V. If the pump slings water through your U.V.Custom Aquarium Advice: Ultraviolet Sterilization chamber too fast, the light cannot effectively penetrate the particles for the necessary amount of time to irradiate them.

To properly irradiate viruses and bacteria, 15,000-30,000 microwatt seconds/cm2 is needed. To irradiate protozoans, 90,000 microwatt seconds/cm2 is needed. Microwatts refer to the quality and power of the bulb, seconds refers to dwell time (the time the water spends in the chamber) and centimeters squared is the distance from the bulb in which irradiation takes place. From the above, you can see that with an improperly controlled flow rate, your U.V. may be effective at killing bacteria and algae, but you could be completely missing the protozoans, which pose a much more serious risk to your livestock. Another key to successful U.V. function is the quality of the light bulb. U.V. lamps must be replaced diligently or you risk losing the integrity of the “microwatt” portion of the calculation- thereby again rendering your U.V. inefficient.

In summary, an ultraviolet sterilizer is a piece of equipment you can’t afford NOT to have – especially when housing marine Angels, Tangs and Butterflies. If you’ve ever painstakingly disassembled a meticulously planned reef tank to catch that one blasted sick fish so you can quarantine and treat for “Ich”, you know that an ounce of prevention is absolutely worth a pound of cure. Stop in to Absolutely Fish today and speak with an M-1 certified aquarist about the most effective way to add a U.V. to your tank, your fish (and corals!) will thank you!  

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