I can't remember if I had any cyano patches before I put it in, Deb. I don't see any right now. When I added it I was reading PO4 at about .25 and after a week it was down to about 0.1. Then I got impatient with testing PO4 and haven't tested since. I'm not running one of those reactors (they're upflow style) but I am running it with my carbon just in a 3" PVC pipe with some eggcrate on the bottom to hold it in and a wee powerhead to pipe water through it. When the water level overflows over the top I clean out the filter socks. I imagine the reactor or at least an upflow style cannister would be more effective, but I was happy with the moderate reduction I got out of it.
I did go and buy a reactor from Big Al's, and I was going to use it on the 72g, but, well, ....
I guess it's less of rush issue now.
Incidentally it hasn't really helped with the odd patch of hair algae, I still have to pull that out manually about once a month.