I am guessing that 2 HOB's plus the canister plus the wet/dry plus the pothos are enough too handle the bio-load
Hello; Not trying to be a jerk with this post. I hear and read often that folks believe a lot of power filters can "handle bio-load". This has some truth but there are limits.
More filter media and surfaces where the water can flow do a couple of things well. First the filter media can trap detritus ( fish waste, excess food, and other particles. These trapped bits can and should be removed on a regular basis. This is good mechanical filtration which keeps a tank looking nice and also can remove some organic junk before it decays and adds thru decay to the "bio-load".
I do not happen to be in the group which favors gently rinsing dirty filter media in tank water and reusing it. I do not want that soiled stuff put back into my tanks. I prefer to replace the filter media with new so it can have the capacity to trap as much detritus as possible.
The second thing power filters do well is to give a place to add what is often called "bio-media" that will be in a good water flow. This is the ceramic media, the bio-balls, the lava rock, the carbon chunks and even glass marbles. The bio media should be placed behind the filter media and to my thinking is not part of mechanical filtration.
This bio media and most other solid surfaces in the tank become places for the beneficial bacteria (bb) to form a bio film of colonies. The bb can make toxic ammonia and nitrites into the much less toxic nitrates. That is where power filters good work ends.
It is my understanding that the best power filters do not remove nitrates. This is where WC and live plants can make a difference.