UV

Question
I have a 90 gallon reef setup with 150-175 live rock asst. soft and lps coral, inverts, etc. I also have an 8w UV sterilizer. I setup a 30 gallon sump with a 16in. micron bag.
Question: Is the UV sterilizer a neccessary piece of equipment for a reef setup.

Thanks.

Answer
Hi Mike. There is a lot of controversy as to weather a UV sterilizer is needed for a reef set up. In my opinion I would have to say that not only is it not needed it may also be potentially detrimental to a reef set up. While UV sterilizers do help with potential parasite infections breaking out and may control some undesirable algae blooms they do not completely solve either of these problems. As a matter of fact they only help control these problems and do not completely eradicate them. The algae spores or the parasite larva that happen to go through the UV unit will be killed(that is if the water flow is not too fast and the bulb does not need replacing) but the ones that don't will still thrive and cause problems. With that said UV sterilizers will also have a detrimental effect on any copepod or planktonic population you may have in your tank. All of these creatures have a free swimming stage or a larval stage at which they may inadvertently be pulled through the UV sterilizer which will kill them as well. As I am sure you know, having a good copepod population in a reef tank helps to keep the corals well fed and completes the food cycle in your tank. The ocean would not support life if it could not support the copepod population. Now a UV sterilizer will not kill all the planktonic creatures in your tank, just as it wouldn't kill all the parasites that may enter your tank, but that coupled with the large quantities of this population that can be consumed by corals will very quickly deplete the population to where they can not reproduce fast enough to keep up with feeding needs. There is a concept known as having a tank that is too clean to support corals properly. A UV sterilizer would be one reason why this would occur in a tank. If you are utilizing a quarantine tank for any newly introduced fish and have good maintenance practices a UV sterilizer is an unnecessary piece of equipment and to many people it may even give them a false sense of security when it comes to their tank. The choice is yours but in my opinion UV sterilizers are best used for ponds where you can not control what may enter into the water from the outside environment. This is the only place they make any sense to use to me.