Who is Using a Refugium for Nutrient Control?

[pterfloth]

I am interested in adding a refugium to my system, primarily to house macroalgae for nutrient control. I was wondering who is already doing this, what your experience has been and what you would recommend for my system. I have a 200 gal display tank and a 33 gal sump at present. I was either going to get a bigger sump and add a refugium section or plumb in a separate refugium.

I currently run zeolites, FM additives and have phosphates of ~0.00 and nitrates of <5 but am interested in a natural alternative.

How big should my refugium be and what type of macroalgae should I consider?

Your input would be very much appreciated.