can you use a UV sterilizer in a reef tank?

Question

I have a problem with yellow algae in my 55 gal reef, due to the metal halides and cf's. I have mushroom coral, leather coral, and an anemone. If I put in a UV sterilizer will it starve the coral and anemone, since they need symbiotic algae to eat ? In other words, does a UV sterilizer kill the same type of algae that corals need to survive? thanks

Answer 1

I think you're confused about what a UV sterilizer does and how it works.

The UV unit attaches to the tubing that goes to an external filter (or you can just use a powerhead and tubing to the UV unit and a return). UV uses radiation from an encased lamp to kill microorganisms that flow through it. It won't kill anything bigger than a few cells in size - this rules out most parasites. It will take care of bacteria and algae spores.

What it doesn't do is kill anything living in your tank already. The zooaxanthellae in your symbiotic corals and anemones won't be harmed, because they will never reach the UV light - they're inside the organisms

UV also won't change the nutrients that your algae is feeding on. The only thing that can remove this is water changes and a good protein skimmer. Do you know what your nitrate and phosphate levels are?

Using both compact fluorescents and metal halides is a bit much for a 55 gallon (I'm guessing this is a full hood with both units in it?). What's your photoperiod? Twelve hrs. should be enough. Light intensity may also be contributing to your algae buildup. Try cutting back on the lighting intensity (eliminate the cf or mh for a few days) or photoperiod (less time on) or both - following a 20-25% water change.

Also, consider a few good herbivores (fish or inverts) that will graze on your algae. Or some macroalgae species (Chaetomorpha or Caulerpa) that will compete with your algae for nutrients. Just be careful of Caulerpa - it can take over a tank!

See the link below for more info: http://www.peteducation.com/article.cfm?cls=16&cat=1789&articleid=1642

ADDITION: I forgot to mention that I'd personally skip the UV - they're expensive and you have to change the lamps yearly to be effective!

Answer 2

Two thumbs up to copperhead if I could. Great answer, listen to him on all things salt!

MM