Hello,
This method is just different, I know that with the other two systems, they rely on their zeolites being shaken so that the surface area is scrubbed, and that way it leads to fresh surface area. With AF, it is not necessary, the zeolites for all practical purposes are quite the same. With AF, you change them out a couple of weeks sooner than the other systems, and AF recommends that with tanks with little live rock, no live rock, and sandless, to add siporax for additional surface are for denitrifying bacteria to grow, they are usually able to be added to the sump and require little to no maintenance. Most are now running in one single fluidized reactor 3 medias. On the bottom Zeomix, then on top of it AF Carbon, and then Phos Minus on top of it. The flow rate is determined by the Phos Minus tumbling gently, as to not escape the reactor. This would allow for further reduction of N&P in addition to the NP Pro(carbon source) and Pro Bio S(bacteria source) additions. Cheers!