I come to this thread quite late, but thought I'd add my $.02 anyway...
An ongoing misconception in the hobby is that beneficial bacteria only or primarily lives in the filter. And of course the makers of expensive bio medias want us to believe this so we continue to buy their products. Now the filter is a great place for BB to live and a colony may very well start there in a new setup. However, beneficial bacteria will inhabit any hard surface and in the established tank (6 months or more) there is typically far more BB in the substrate than in any filter.
Now I'll admit that I once thought that the filter traps organic matter where it decomposes and pollutes the water so we are best served by getting the crud out of the system the sooner the better. Perhaps somewhat valid, but only if you clean the filter every day!
In later years I've come to realize that much like the substrate, the filter is best left undisturbed where the biology can mature and do it's best job for us. Now all of my filters are completely fillled with sponge material. I find that sponge material is not only great for mechanical filtration, but also the perfect platform for beneficial biology. And these days I let filters run until there is a noticeable reduction in output flow. Then I will clean the filter at least enough to restore proper flow.
Now I have untreated well water, but even if I didn't I would clean under the tap and leverage the sink sprayer.
For a deep dive, check out
Filtration and Water Quality.