Another update …...
Today I cleaned the filters in a different tank, another 125 gallon, filtered by three AC 500's (110). The tank contains a single adult male A. citrinellus that is 13-14" in TL. He is a big brute, with a big appetite, and he leaves a fair share of solid waste behind each week. This tank receives a very large 85% water change each week, but a good portion of the waste ends up in the filters, as there is no substrate in this tank, and with three big AC's running there is plenty of water movement. Along with what this brute of a fish kicks up!
This tank is also treated once a week with 1/4 teaspoon of Bio-Clean.
The following filter was cleaned 11 weeks ago. At that time I also added a new sheet of white Pen Plax media, that sits directly on top of the main course sponge. Photo taken 11/29/19
This is the same filter today, 2/22/20, photo taken prior to cleaning.
Look how clean the main sponge is, before I even rinsed it!