[big 5]

refugiums are to have macro algae or xeina to take up excess nutrients to keep hair and other type of algae's out of the display tank
just a thought
why not have a refugium with a bad algae to keep display clean
put a light with bad spectrum on the refugium to promote algae growth
algae has spores that travel in the water so to keep spores from reaching your tank run a uv on returning water to your sump
i was going to set this up as an experiment but i'm worried about all my livestock incase it backfires
just want to hear thoughts on this idea
my friends system has hair algae (and macro algae) in his sump for about 6 months now with no ill effects on his display
just made me think
not here to get bashed just an idea

[Reefland]

Some people get side tracked by the terms being used first of all. A refugium is a safe haven for desired animals that would normally be preyed on in the siplay to grow and reproduce safely, in turn becoming food source for the display. People have started using this extra tank just for harvesting macro algae, which isn't really the defined purpose of a refugium. Just my thoughts on that even though you didn't ask about it.

Anthony Calfo uses the term "vegetable filter" and I think this is more suiting for what you are describing (not that it really matters). What you are invisioning is a great idea, although I don't think the UV is necessary. Using an external tank for the growth and harvesting of various types of algaes is sucessfully used by many aquarists and should be considered by everyone when setting up systems and determining their method of nutrient export. Whether is it various Caulerpa sp., or other macro and micro algaes; using an external box to grow them (thus using up nutrients from the total system) and keeping them from the display is a good idea.

[zhenya]

I agree with Scott on that the UV isn't necessary at all. If one using refugium with Caulerpa or some other algae for filtration purposes then one needs to stay on top of its growth and harvest it regularly to prevent sporulation. Other then that there is no risk of the spores getting to display tank.
Pruning back algae as it consumes nutrients and grow in principle is the way an algal refugium works,I believe.