Kind of hit and miss. I personally now change out Phosban at about 6 weeks for my system. I started out changing it out every month and have increasing it slowly to see what works best. Good stuff this ferric oxide phosphate remover IMO.
Glad to see this question, for I was about to post about something similar. I ahve been using phosban since MACNA where I got some free samples from Julian Sprung. Along with my water changes, it is the only thing in 9 months that has almost erradiacted my man eating bryopsis epidemic. It is not gone 100%, but the tiny patch that is left could be plucked by hand very easily. Before, there was so much of it I was almost afraid of being eaten alive by it.
I thought that having the bags suspended in the sump was helpful, but like chrisrd, I fell it would be more efficiently used if I put it in some sort of chamber where water flows right through every grain. I was going to ahve someone build me a custom chamber, but I think I will just get 2 of these and divide the output from my UV filter to run through both of them. That should work well I think.
I've never used activated carbon actually, but I may just get 4 chamber altogether and have 2 with phosban and 2 with carbon. Let the carbon go first and from there into the phosban. I don't even need any new pumps since I can put this outlet to work as said above.
Just an idea.
Thanks for the link Bowfront!
I read another article similar to the one you posted. The one I read suggested to run the carbon in a chemical reactor as I mentioned before, & to supply the water by a small powerhead ran on a timer?