Just came in to this thread. I had a problem with red turf algae, and found that BRS site too. I use the reactor they recommend and their GFO, and I've seen my algae population practically melt away.
It doesn't treat the root problem, but it definitely helps keep the phosphates in check. I have a 100g tank, and I run 1 cup of GFO in the reactor cheanged every couple o' months.