I have two of these running on my 90 gal. I use the 2x30ppi and 2x20ppi pads in one of them, basket two is filled with fluval biomax, and basket three has some bio-max and micro pad. I use carbon from time to time but pretty much use mechanical and bio media only. In my other one I use standard filter pad/floss, biomax in the second basket, and carbon bag and micro pad in the third basket. I replace the pads maybe once or twice a year, I normally just rinse them in a bucket of aquarium water once a month or so. When I was new to the hobby, I followed manufacturer's recommendations of replacing everything all the time and broke the wallet before I wised up and realized that replacing things destroys your bb colony, and when you do replace items you are supposed to stagger it.