Hello; I think what is being suggested is that the beneficial bacteria (bb) your tank should have need surfaces on which to grow.
I tend to part ways a bit with many on just what these surfaces can be. Some tend to assume the surfaces in a filter are where the bb will colonize. While this is true, I feel that the bb will colonize on many other surfaces as well. My take being most any solid surface will have some bb. I also think there is likely to be more bb colonies where there is some water flow.
My thinking being that one type of bb feed on ammonia and the other feed on nitrites. These "bb foods" are in the water. However the bb themselves are a film (bio film) almost entirely on solid surfaces and very little in the water itself.
Back decades ago before power filters were common I ran tanks on filters operated by air pump bubblers. Very little water flow compared to modern power filters.
I also usually ran the under gravel filters (UGF). I still do. These filters set up a flow thru the substrate and in effect make the substrate into a bed for the bb to colonize. Now a days these UGF's can be run by powerheads and can be set up to have reverse flow which should make the substrate an even better bb bed.
Yes you can go the multiple power filter route that have chambers for media designed to give the bb a place to make a home and that will work.
One other question. Do you run an air bubbler? I have run them in nearly all tanks for decades. Lots of positive stuff with their use.
